ln/ccd detector manualevryan/mro/pi1k/ln-ccd detector manual.pdf12 ln/ccd detector manual version...

4411-0013Version 2.D

July 31, 2001

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�Copyright 2001 Roper Scientific, Inc.3660 Quakerbridge RdTrenton, NJ 08619TEL: 609-587-9797FAX: 609-587-1970

All rights reserved. No part of this publication may be reproduced by any means without the writtenpermission of Roper Scientific, Inc.

Printed in the United States of America.

The information in this publication is believed to be accurate as of the publication release date. However,Roper Scientific, Inc. does not assume any responsibility for any consequences including any damagesresulting from the use thereof. The information contained herein is subject to change without notice.Revision of this publication may be issued to incorporate such change.

iii

Table of Contents

Chapter 1 General Information........................................................................... 7Introduction.........................................................................................................................7Environmental Conditions ..................................................................................................7General Features..................................................................................................................7Detector Windows...............................................................................................................9

Shutter...........................................................................................................................9Vacuum.........................................................................................................................9Array.............................................................................................................................9

Chapter 2 Detector Setup ................................................................................. 11General Instructions ..........................................................................................................11

Connecting the detector ..............................................................................................11Setting the controller ..................................................................................................11

Imaging Applications ........................................................................................................11Connecting lenses .......................................................................................................11Overexposure protection.............................................................................................12

Spectroscopic Applications...............................................................................................12Focal Plane Distance ..................................................................................................12Deep focal plane .........................................................................................................13Shallow focal plane ....................................................................................................13Entrance slit shutter ....................................................................................................14Overexposure protection.............................................................................................15

Chapter 3 Filling the Dewar .............................................................................. 17Introduction.......................................................................................................................17Holding Times...................................................................................................................17Setting the Operating Temperature ...................................................................................18

ST-133 Controller.......................................................................................................18ST-138 Controller.......................................................................................................18

Begin Data Collection .......................................................................................................19Filling the Dewar...............................................................................................................20Dewar Options ..................................................................................................................21

LN Autofill .................................................................................................................21All-directional Dewar .................................................................................................21

Chapter 4 Focusing ........................................................................................... 23Baseline Signal..................................................................................................................23Shutter ...............................................................................................................................24

Overheating ................................................................................................................24Imaging Systems ...............................................................................................................24

Imaging Field of View................................................................................................25Spectroscopy Systems.......................................................................................................26

Focusing and Alignment of Array Detectors..............................................................26

iv LN/CCD Detector Manual Version 2.D

Appendix A Outline Drawings .......................................................................... 27

Appendix B Vacuum Restoration..................................................................... 29Introduction.......................................................................................................................29Vacuum Pumpdown Procedures .......................................................................................30

Procedure #1 ...............................................................................................................30Procedure #2 ...............................................................................................................31

Appendix C Autofill System ............................................................................. 33General Information ..........................................................................................................33Unpacking the System.......................................................................................................34System Components..........................................................................................................34Model 186 Front and Rear Panel Controls and Connectors..............................................35

Front Panel..................................................................................................................35Rear Panel...................................................................................................................36

Setting up the System........................................................................................................36Calibration.........................................................................................................................39

Introduction ................................................................................................................39Relations between Calibration and Sensor Length .....................................................39

Calibration Procedure........................................................................................................39Introduction ................................................................................................................39Resetting the MAX/MIN Calibration Points and Cadj Factor....................................40

Operation...........................................................................................................................41Turn on the Model 186 ...............................................................................................41Active Length Setting.................................................................................................41HI and LO SETPOINTs..............................................................................................42A and B SETPOINTs..................................................................................................42Controller Output Receptacle Operational Mode .......................................................43Fill Timer INTERVAL...............................................................................................43Units Display Output ..................................................................................................44

Serial Communication.......................................................................................................44Serial Port Connector and Cabling .............................................................................44Command/Return Termination Characters.................................................................44Serial Communication DIP Switch Settings...............................................................45Serial Command Set Reference ..................................................................................46

J2 Connector Pinout ..........................................................................................................49RS-232 Cable DB-25 to DB-9 Translation .......................................................................50RS-422 Cable Wiring........................................................................................................50Dielectric Constants for Common Liquids........................................................................51Troubleshooting ................................................................................................................51Custom Instrument Configurations ...................................................................................54Additional Technical Support ...........................................................................................54

Return Authorization ..................................................................................................55Specifications ....................................................................................................................55

Level Measurements...................................................................................................55Operating Parameters .................................................................................................55Power Requirements...................................................................................................55Physical.......................................................................................................................55Environmental ............................................................................................................55

Table of Contents v

Declaration of Conformity................................................................................. 59

Appendix D Swagelok Fittings ......................................................................... 57Installation.........................................................................................................................57High Pressure Applications or High-Safety-Factor Systems ............................................58Retightening Instruction....................................................................................................58

FiguresFigure 1. LN/CCD Detector...............................................................................................7Figure 2. LN/CCD Detector, side view..............................................................................8Figure 3. Nikon lens adapter ............................................................................................12Figure 4. Adapter for a deep ............................................................................................13Figure 5. Shallow focal plane spectrometer .....................................................................14Figure 6. Shallow focal plane spectrometer type 2 detector ...........................................14Figure 7. One type of entrance slit shutter mount ............................................................14Figure 8. Second type of entrance slit shutter mount .......................................................15Figure 9. WinView/32 Detector Temperature dialog box................................................18Figure 10. Temp. knob, located on the front of the controller .........................................19Figure 11. Dewar Ports and Valves..................................................................................20Figure 12. Imaging field of view......................................................................................25Figure 13. Side-On Dewar, wide fill port.........................................................................27Figure 14. Side-On Dewar, narrow fill port .....................................................................28Figure 15. End-On Dewar ................................................................................................28Figure 16. Pumpdown Adapter ........................................................................................31Figure 17. Adapter mounted and connected to Vacuum System ....................................31Figure 18. Knob pulled out ..............................................................................................31Figure 19. Autofill System...............................................................................................33Figure 20. Model 186 instrument, control valve and sensor system diagram..................38

TablesTable 1. CCD Array vs. Spectrometer Mount..................................................................13Table 2. Approximate Temperature Range vs. CCD Model ............................................17Table 3. Typical Values for Setpoints..............................................................................43Table 4. Dielectric Constants for Common Liquids.........................................................51

Index ....................................................................................................................65

Warranty & Service ............................................................................................61 Limited Warranty: Roper Scientific Analytical Instrumentation...................................... 61

Basic Limited One (1) Year Warranty ....................................................................... 61 Limited One (1) Year Warranty on Refurbished or Discontinued Products .............. 61 Shutter Limited One Year Warranty .......................................................................... 61 VersArray (XP) Vacuum Chamber Limited Lifetime Warranty................................ 62 Sealed Chamber Integrity Limited 24 Month Warranty............................................. 62 Vacuum Integrity Limited 24 Month Warranty ......................................................... 62 Image Intensifier Detector Limited One Year Warranty............................................ 62 X-Ray Detector Limited One Year Warranty ............................................................ 62 Software Limited Warranty........................................................................................ 63 Owner's Manual and Troubleshooting ....................................................................... 63 Your Responsibility.................................................................................................... 63

Contact Information.......................................................................................................... 64

vi LN/CCD Detector Manual Version 2.D

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7

Chapter 1General Information

IntroductionLiquid nitrogen cooled CCD detectors (LN/CCDs) areideal for low to ultra-low light level applications requiringvery long integration times. They have a wide spectralrange, a high dynamic range, high thermal and temporalstability, and excellent geometric accuracy and stability.

Special-purpose LN/CCD detectors utilize X-ray or UVsensitive devices. Operation of these detectors is nearlyidentical to operation of the standard LN/CCD detector.

If you have a detector with a UV scintillator coatedCCD, protect it from excessive exposure to UVradiation. This radiation slowly bleaches thescintillator, reducing sensitivity.

Environmental Conditions� Storage temperature �55°C

� Operating environment 30°C > T > -50°C

� Relative humidity �50%. High humidity climates may require continuous flushing ofthe spectrometer’s exit port with nitrogen. See the window information below.

General Features� Compact and lightweight design allows easy interfacing with various spectrometers

and alignment with optical systems.

� Widest range of temperature control: QE vs. dark charge.

� Maximum user safety: Three different valves protect against pressure buildup eitherin the LN container or in the vacuum vessel.

� Minimum requirements for frequent pumping: Various adsorbents and desiccants areadded to trap contaminants.

� A safe pumping interface: Princeton Instruments uses a helium-leak tested valve thatensures ease in interfacing to vacuum pumps with a minimal chance of opening to theatmosphere.

� The CCD array is placed as close as possible to the Dewar window in order to allowinterfacing to most spectrometers or lenses with an on-Dewar shutter.

CAUTION

Figure 1. LN/CCD Detector

8 LN/CCD Detector Manual Version 2.D

Never remove the detector’s front window; ice will form immediately, destroying thearray. Operations requiring contact with the device can only be performed at the factory.

Never operate the detector cooled without proper evacuation. This could destroy theCCD!

Ice buildup may occur at the valve ports if the detector is being operated under highhumidity conditions. If frost appears on the valves, periodically clean the outside of thevalves so that ice does not prevent the valves from venting normally.

LN/CCD detectors have several sections. The front enclosure contains the CCD arrayseated on a cold finger. This finger is in contact with the LN Dewar and has a heater toregulate the CCD temperature. The front enclosure opens into the vacuum jacket thatsurrounds the internal LN Dewar.

The Dewar is filled through a sealable top opening, and has two pressure relief valvesoperating at 1 and 10 psi to safely vent N2 gas. A special “all-directional” Dewar optionis also available, which allows the Dewar to be operated in any orientation.

The electronics enclosure contains the preamplifier and array driver board, keeping allsignal leads to the preamplifier as short as possible, and providing complete RF shielding.

Filler plug

Safety pressure relief valvesfor venting nitrogen gas

Connector (DB25F) forthe controller cable

Pressure relief valve, opens ifpositive pressure occurs in thevacuum enclosure

Connector for shuttercontrol cable

CCD

Shutter control cable

Mechanical shutter housing

Safety cap

Vacuum valve

Swagelokplug

Vacuum valve

Vacuum Valve Assemblyon Older Versions

WARNINGS

Figure 2. LN/CCD Detector, side view

Chapter 1 General Information 9

Detector Windows Three windows separate the CCD from the outside. Each has a specific function, and twoare optional or removable.

Shutter

This window on the front of the shutter housing protects the shutter and also ensures thatthe shutter enclosure remains in a dry nitrogen environment, if applicable. This preventscondensation on the outside surface of the Dewar window (in labs with high humidity).This window can be easily removed by the user.

Vacuum

This window maintains the vacuum in the Dewar. It is made of the highest quality quartzavailable. The following optional coated vacuum windows are available:

� UV/AR coated for operation in the 200 - 420 nm range.

� VIS/AR coated for operation in the 400 - 750 nm range.

� NIR/IR coated for operation in the 580 - 1050 nm range.

� Broad-band MgFl coated for operation in the 200 - 1100 nm range.

Wedge windows can be provided if specified at time of order. Also, if a coated vacuumwindow is specified, the other detector windows may not be installed.

Array

This is provided primarily for protection of the array in case of accidental loss of vacuumwhen the array is very cold. The standard window is made out of the highest qualityquartz. This window can be replaced with any of the optional windows mentioned above,or Roper Scientific can provide the CCD without the protection window.

If you see problems that resemble window interference patterns, contact the factory.

11

Chapter 2Detector Setup

General Instructions Two items are applicable to both imaging and spectroscopic systems.

Connecting the detector

Each detector is supplied with a cable to connect to the controller. Make sure that thecontroller is off, then connect the larger end of the cable to the port marked “detector” onthe controller. Tighten the screws in place. Connect the smaller end of the cable to thedetector, and tighten the screws.

Setting the controller

Any user who will be running both TE/CCDs and LN/CCDs with their controller mustensure that the internal power supply switches of the controller are set properly (appliesonly to those Controllers which have internal switches). Consult the controller manual forinstructions on setting these switches.

Note: If you have purchased one detector only, the Controller switches will have beenset correctly at the factory. No user adjustment will be needed.

Imaging Applications This section describes how to connect lenses to the detector for imaging applications.Instructions for spectroscopic applications appear later in this chapter.

Connecting lenses

Detectors for use in imaging systems (cameras) are shipped with the lens mount alreadyattached. Standard Princeton Instruments lens mounts use the Nikon bayonet format, asshown in Figure 3. This can be converted to most other formats using commerciallyavailable adapters. If your optical system cannot be converted to this format, contact thefactory. Other mounts may be available. Consult the factory for specific informationrelating to your needs.

To mount the lens on the camera, locate the large indicator dot on the side of the lens.There is a corresponding dot on the front side of the adapter. Line up the dots and slidethe lens into the adapter. Turn the lens counterclockwise until a click is heard. The lens isnow locked in place.

If the front part of the lens mount rotates with the lens, tighten the setscrews until it isfixed in place. Fine adjustments are covered in Chapter 4.


To remove the lens, locate the lens release lever at thefront of the lens mount. Press the lever toward thecamera housing, and at the same time rotate the lensclockwise. Then pull the lens straight out.

Many standard microscope adapters are also availablethrough Roper Scientific. Attach the adapter to thelens mount provided with the detector. Connect theadapter to the microscope. See the adapter literaturefor further directions.

The LN/CCD Dewar must never be tilted more than 30° from vertical, unless the “all-directional” Dewar option has been purchased. For this reason, an end-on type and a side-on type are available for different mounting situations. If mounting the Dewar to yoursystem requires you to exceed the 30° limit, you may have the wrong type of Dewar.Contact the factory.

Overexposure protection

Cameras that are exposed to room light or other continuous light sources will quicklybecome saturated. Set the lens to the smallest aperture (highest f-number) and cover thelens with a lens cap to prevent overexposure. Continue with the cooling instructions inChapter 3.

Spectroscopic Applications The detector must be properly mounted to the spectrometer to take advantage of all theavailable grouping features. Additional precautions must also be taken to preventoverexposure of the detector.

At the time of purchase, both the Dewar and the adapter were selected for your specificapplication. Consult the diagrams to determine which type of adapter is needed.

The LN/CCD Dewar must never be tilted more than 30° from vertical, unless the “all-directional” Dewar option has been purchased. For this reason, an end-on type and a side-on type are available for mounting to vertical and horizontal image planes, respectively.If mounting the Dewar to your system requires you to exceed the 30° limit, you may havethe wrong type of Dewar. Contact the factory.

Focal Plane Distance

The distance to the focal plane from the front of the mechanical assembly depends on thespecific configuration as follows.

Figure 3. Nikon lens adapter

WARNING

WARNING

Lens release lever

Front part of adapterfor adjusting focus

Set screws to lock front part of adapter in place

Chapter 2 Detector Setup 13

Mounting Flange to Focal Plane (no shutter or adapter): 0.440±.01�

Front of Shutter to Focal Plane: 0.894±.01�

Front of 7050-0032 Large Detector Adapter to Focal Plane: 0.590±.01�

Note: The large shutter has a 3.88� bolt circle. The 7050-0032 adapter, all PDAs andICCDs have a 3.60� bolt circle.

Deep focal plane

For spectrometers with a focal plane 25 mm or morebeyond the exit interface, the shutter housing remainsconnected to the detector. Such spectrometers includeActon (adapters are available for all Acton models), theISA HR320, ISA HR640, Chromex 250IS, and mostinstruments that are 1 meter or longer. (If you are not sureof the exit focal plane depth, contact the spectrometermanufacturer.) Adapters for these spectrometers aregenerally in two pieces, as shown in Figure 4.

To mount flange 2, place it over the shutter housing andbolt it to the shutter using the screws provided.

Next, loosen the setscrew(s) on flange 1, then mount this flange to the spectrometer. Slideflange 2 into flange 1. Do not tighten the setscrew(s) until focusing and alignment arecompleted in Chapter 4.

Shallow focal plane

For spectrometers with a focal plane distance less than 25 mm, the shutter provided can eitherbe mounted on the entrance slit of the spectrometer or operated as a stand-alone shutter.

The detector mount provided in these cases does not allow focusing via the adapter.Focusing must be accomplished by adjusting the spectrometer. Consult the chart below todetermine the type of mount for your CCD.

CCD Type of Mount

EEV 576 Type 1

All other EEV Type 2

All SITe (Tektronix) Type 2

Table 1. CCD Array vs. Spectrometer Mount

For a type 1 detector, mount the flange to the detector using the two half-rings and thescrews provided as shown in Figure 5. Note that the tapered side of each half-ring faces theadapter. Next, screw the 10-32 hex screws halfway into three of the six tapped holes in thespectrometer’s exit plane. Position the detector so the three hex head screws line up withthe openings in the adapter flange. Slide the detector over the screws and rotate into theproper orientation. Leave the detector free to rotate until it is aligned in Chapter 4.

Figure 4. Adapter for a deepfocal plane spectrometer

Flange 1 Flange 2

Setscrew


For a type 2 detector, mount the adapter to the spectrometer first. Then insert the front ofthe detector into the adapter, and thread it into place using the large captive ring nut onthe detector, as shown in Figure 6.

Flange

Half rings Adapter Ring nut

Figure 5. Shallow focal plane spectrometertype 1 detector

Figure 6. Shallow focal plane spectrometer type 2 detector

Entrance slit shutter

This shutter can either be mounted on the entrance slit of the spectrometer or used as astand-alone shutter. Shutters for stand-alone operation have two tapped holes formounting to a stand: one metric, the other English.

Entrance slit shutter mounts come in twotypes. The first type is for use with CP-200 and HR-250 Spectrometers, and isshown in Figure 7.

Remove part 1 by removing the fourPhillips screws. Place part 2 over theentrance slit, and mount it by threadingpart 3 to the spectrometer. Replace theshutter and part 1.

Figure 7. One type of entrance slit shutter mount

1 2

3


The second type of shutter mount requires no disassembly. It isused with all Acton spectrometers. Mount it to the detector asshown in Figure 8.

Connect the shutter cable to the side of the detector. Longercables are available from the factory.

Overexposure protection

Detectors that are exposed to room light or other continuouslight sources will quickly become saturated. This most oftenoccurs when a shutter is not used. To reduce the incident light,close the entrance slit of the spectrometer completely.

Figure 8. Second type ofentrance slit shutter mount

17

Chapter 3Filling the Dewar

It is generally good practice to turn on the controller and start at least one data collectionwhile the detector is cooling down, and then to keep the controller in operation for theentire time the Dewar contains LN2. This will establish and maintain the “keep cleans”mode of the controller so that, even when the CCD is not actively taking data, it will becontinuously cleaning (shifting charge on the array to clear dark charge and cosmic rayartifacts).

Introduction LN/CCD detectors use liquid nitrogen to reduce the temperature of the CCD. The liquidnitrogen is stored in a Dewar that is enclosed in a vacuum jacket for minimal externalthermal losses. The chip temperature is regulated by a heating element driven by closed-loop proportional control circuitry. A thermal sensing diode attached to the cooling blockof the detector monitors the chip temperature. The temperature can be thermostated overa 40° to 50° range Celsius. The exact range depends on the CCD device, as indicated inthe following table.

CCD Model Approximate Range

1024HER, 1024EHRB -50°C to -100°C

All other arrays. -80°C to -120°C

Table 2. Approximate Temperature Range vs. CCD Model

LN/CCDs, because of their low operating temperatures, must always be connected to anoperating controller. If the controller power is turned off with liquid nitrogen remainingin the Dewar, the CCD will quickly become saturated with charge, which cannot bereadily removed without warming the detector to room temperature.

Holding Times With small CCDs, e.g., 1152 × 298, 1024 × 256, 576 × 384, etc., the LN hold time usinga 500 ml Dewar is approximately 12 hours at the lowest temperature setting. With largerCCDs, e.g., 512 × 512, 1024 × 1024, or 1152 × 1242, the hold time of the same Dewar isreduced to 9-10 hours. Princeton Instrument’s Dewar (1.7 liters) has a hold time of 25hours or more, again depending on the array size and operating temperature. The1024HER and 1024EHRB arrays, due to their higher operating temperature, have an18-hour hold time.

To maximize the holding time when leaving the detector overnight, in addition to toppingoff the Dewar, you will want to turn off the heater switch (on the front panel of the

ATTENTION

CAUTION


ST-138 Controller; in the case of the ST-133 Controller, you must set the arraytemperature to its lowest operating temperature, typically -120� C, through the software).You must leave the controller power on in either case. This will bring the CCD to itsminimum operating temperature and will minimize LN evaporation. This should keep thedetector cold for 36 to 48 hours. The following day, turn on the ST-138 heater switch toreturn the CCD to its operating temperature. If using an ST-133 Controller, you must setthe temperature to the operating temperature via the Detector Temperature panel in thesoftware.

Setting the Operating Temperature

ST-133 Controller Temperature control is done via software. Oncethe desired array temperature has been set, thesoftware controls the thermoelectric coolingcircuits in the camera so as to reduce the arraytemperature to the set value. On reaching thattemperature, the control loop locks to the settemperature for stable and reproducibleperformance. The green TEMP LOCK indicatoron the Analog/Control module panel lights toindicate that temperature lock has been reached(temperature within 0.05°C of set value). If using WinView/32, there will also be aLocked indication in the Detector Temperature dialog box ( Figure 9). This on-screenindication allows easy verification of temperature lock in experiments where thecomputer and controller are widely separated. There is also provision for reading out theactual temperature at the computer so that the progress of the cooldown can bemonitored.

The time required to achieve lock can vary over a considerable range, depending on suchfactors as the camera type, CCD array type, type of cooling, etc. Once lock occurs, it’sokay to begin focusing. However, you should wait an additional twenty minutes beforetaking quantitative data so that the system has time to achieve optimum thermal stability.

ST-138 Controller1. Turn the cooler switch on the front of the controller off. Then turn the power switch on.

2. Locate the temp knob on the front of the controller. The dial reads in units of minusdegrees centigrade. See the diagram to locate the locking tab (1). Turn this tabcounterclockwise until the Temp knob is free to rotate.

Note: For initial data collection, set this knob to -80°C.

3. On the top side of the Temp knob is a rectangular window that denotes hundreds of°C. Each complete turn of the knob is -100°C. Around the moveable part of the knobare numbers from 0 to 99, in increments of 2. Turn the knob until the correct value (0or 1) appears in the hundreds’ box. Then turn the knob until the desired valuebetween 0 and 99 appears below the box. Turn the locking tab clockwise to lock theTemp knob in place.

Figure 9. WinView/32 DetectorTemperature dialog box


Locking tab

×100°C

×1°C

4. In Figure 10, the knob on the left is set to -90°C. The locking tab is shown in theunlocked position. On the right, the temperature is set to -100°C and the locking tabis in the locked position. Note that the rectangular window reads “1” in this case.

Note: Working at excessively low temperatures, i.e., below -120°C, is notrecommended. Dark charge at this temperature is completely insignificant and any furtherreduction in temperature substantially reduces the spectral response (QE), particularly inthe red and for BI and BIDD devices. Transfer efficiency is also reduced at thesetemperatures.

5. Turn the Cooler switch on. If the LN/CCD is set below -140°C the Low Temp Limitindicator (red LED) will light. Set the temperature to a higher value to deactivate theindicator.

Begin Data Collection1. Begin with the detector blocked off. For an imaging system, set the lens at the

smallest possible aperture (largest f-number). For a spectroscopic system, close theentrance slit of the spectrometer completely.

2. Set the software to the Freerun and Asynchronous modes (consult the softwaremanual if you are not familiar with these modes). Choose a fast exposure, and begindata collection.

3. Continue data collection until the CCD has reached the operating temperature.Collection may then be stopped, but the controller must always be left on. If thecontroller is turned off the CCD will become saturated, requiring the detector to bewarmed to room temperature.

Note: Exposing the CCD to bright light (10× saturation) when cold (<-70°C) will causethe dark current in the exposed pixels to be 3 to 10 times higher than normal for thatoperating temperature. This effect is due to the formation of temporary traps. The effectcan be reversed by allowing the detector to warm up to room temperature.

Figure 10. Temp. knob, located on the front of the controller


Filling the Dewar

Even minimal contact with LN can cause severe injury to eyes and skin. Avoid contactwith the splashing that will invariably accompany pouring LN into a room temperatureDewar.

1. After the detector has been properly evacuated, loosen the retaining nut (Figure 11) afew turns, then remove the LN Dewar port cap by pulling it straight out.

Always be careful when removingthe LN port cap if there is LNpresent in the Dewar. Pressure dueto nitrogen gas can cause the cap tofly out when the retaining nut isloosened, possibly spraying youwith liquid LN, which can causesevere injury.

Dewar port cap

Retaining nut

Pressure relief valves

Figure 11. Dewar Ports and Valves

2. It is recommended that an LN transfer Dewar with a pouring spout be used to transferLN from the storage tank to the detector. If you are going to use a funnel, place a thinvent tube into the Dewar through the funnel to reduce splashing due to boiling LN.

3. Pour approximately 100 ml of LN into the Dewar. Stop for 5-10 minutes until youobserve a “geyser-like” vapor burst from the Dewar opening. This burst is normaland has to do with reaching a thermal equilibrium between the LN and the Dewarcontainer surfaces.

4. Fill up the Dewar (approximately 1.7 liters of LN for standard Dewar or 0.7 liters foran all-directional Dewar). To test the LN level, insert a straight piece of wire (acryogenic “dip stick”) into the Dewar briefly, then remove it. The LN level will beindicated by the condensation on the wire.

5. Once the Dewar has been filled, replace the filler cap and hand-tighten the retainingnut by giving it about 3/4 turn (or more) beyond the point where the nut feels snug.

Ice buildup may occur at the valve ports if the detector is being operated under highhumidity conditions. If frost appears on the valves, periodically clean the outside of thevalves so that ice does not prevent the valves from venting normally.

6. Once a temperature of -80°C has been achieved, maintain the CCD at thattemperature for 2-3 hours, then reset the dial to the desired temperature. Thisprocedure prevents any residual water vapor (if introduced during shipment or

DANGER

DANGER

WARNING


through erroneous pumping in your lab, e.g., if your trap is inefficient) fromcondensing on the CCD window.

If the Dewar is continuously refilled, this procedure is unnecessary and the dial canbe set at the desired temperature without the intermediate -80°C stage.

Note: The pressure relief valves (Figure 11) underneath the protective covering willoccasionally emit a plum of N2 gas and mist. Continuous hissing indicates that thevacuum in the Dewar jacket is probably inadequate. In this case, first remove all LN fromthe Dewar, then reconnect the detector to the vacuum pump.

The cooler status indicator will turn from orange to green to indicate that the temperatureis thermostated to within ±0.050°C. For an LN/CCD to reach -100°C normally requires45-55 minutes.

Note: Temperature regulation does not reach its ultimate stability for at least 30 minutesafter the green indicator LED has turned on. After this period of time the desiredtemperature is maintained with great precision.

Dewar Options Roper Scientific offers a standard capacity Dewar that holds 1.7 liters of LN in a side-looking orientation.

LN Autofill

Roper Scientific also offers an automatic LN feeding system where the LN flows from alarge tank (31-liter capacity) to the Dewar after a preset interval (e.g., 6 hours) or whenthe liquid level falls below a setpoint. The entire filling procedure is fully automatic andonly requires refilling the tank every 2-4 weeks. Currently, this option is only availablefor side-looking detectors. See Appendix C for instructions concerning this system.

All-directional Dewar

Also available is the “all-directional” Dewar that can operate in any angular orientation,but hold only about half as much LN as the normal versions, 0.7 liters. This reducedcapacity translates to half the hold time as well.

Note: There is no simple way to verify whether you have been shipped an all-directionalsystem simply by observing the detector. If you are uncertain, check the shippingpaperwork to verify that your Dewar is an all-directional model.

For operation of the all-directional Dewar in a 90° orientation you can refill the Dewaronly through a special 90° funnel provided by Roper Scientific. For operation at greaterthan 90° angles, there is only one refilling choice:

The Dewar must be returned to a 0° orientation for refilling.

23

Chapter 4Focusing

Detectors for both imaging and spectroscopic applications must be focused for maximumresolution. Imaging applications require adjustment of both the lens and the lens adapter.Spectroscopic applications demand both focusing and alignment of the spectrum.

Baseline Signal With the detector completely blocked, the CCD will collect a dark charge pattern,dependent on the exposure time and detector temperature. The longer the exposure timeand the warmer the detector the larger and less uniform this background will appear.

Note: Do not be concerned about either the DC level of this background or its shapeunless it is very high, i.e., > 1000 counts. What you see is not noise. It is a fullysubtractable readout pattern. Each CCD has its own dark charge pattern, unique to thatparticular device. Every device has been thoroughly tested to ensure its compliance withRoper Scientific's demanding specifications.

If you observe a sudden change in the baseline signal you may have excessive humidityin the detector vacuum enclosure. Turn off the controller, remove the liquid nitrogen, andpump the detector for 30 to 60 minutes. If problems persist call the factory.

All CCD arrays have been tested for uniformity and do not exhibit any vignetting(reduction of response) at the extreme ends of the array. If you do measure such reductionin response across the array, it may be the result of one or more of the followingconditions:

� Condensation of water on the edges of the array window has occurred. This shouldnot happen unless the cooling/pumping instructions, previously mentioned, were notfollowed or if the Dewar has sprung a leak (a rare situation).

� The arrays are held with a special mask that has been designed to minimize reflectionand stray light. These masks were designed to allow light rays to enter through theDewar window even at very wide angles (> f/1.5). If vignetting is observed, it ispossible that your experiment exceeds these angular constraints. Roper Scientificmeasures the array response with a collimated uniform light source to prevent suchfalse bias results.

CAUTION


Shutter Most experiments will utilize the shutter provided by Roper Scientific. It is important torealize the limitations of the shutter, including its mechanical lifetime. These shutters aredesigned to be easily replaced. In case a shutter does cease functioning, contact thefactory.

Every shutter housing has a window to protect the shutter mechanism from external dustand humidity. Since each window causes a small signal loss, all shutters supplied byRoper Scientific have a removable window. Added caution must then be used in thehandling and storage of the detector.

Note: Electromechanical shutters typically have a lifetime of a million cycles or more.Avoid running the shutter unnecessarily. Also avoid using shorter exposure times andhigher repetition rates than are required.

Disconnecting or connecting the shutter cable to the detector while the controller is oncan destroy the shutter or the shutter driver in the controller!

Overheating

The 25 mm shutter for spectroscopy has a built-in thermal interlock to preventoverloading of its coil. If run at a high repetition rate, the shutter may heat enough totrigger the interlock, disabling the shutter.

If your shutter suddenly stops running, stop the experiment and wait. The shutter shouldresume functioning when it has cooled down sufficiently, typically within an hour. Avoidrepeating the conditions that lead to the shutter overheating, or take breaks between datacollections.

Larger shutters do not normally exhibit thermal overloading, so they do not require athermal interlock.

Imaging Systems1. If the software is not yet running, set it to the Freerun and Asynchronous modes.

2. Slowly uncover the lens. If the image becomes washed out cover the lens quickly,and choose a shorter exposure.

3. Adjust the exposure until a suitable value is found. Check the brightest regions of theimage to determine when the full scale of the A/D converter is being used.

4. Place a suitable target in front of the lens. An object with text or graphics works best.

5. Set the focus adjustment of the lens to the correct distance between the camera andthe object. The lens mount is in two sections to further adjust the focus. Loosen thesetscrews with a 0.050� Allen wrench. Then rotate both the lens and the front part ofthe adapter until the image comes into focus. Tighten the setscrews. All focusing maynow be done with the adjustment on the lens.

Microscope adapters follow a similar procedure, except in this case the front part of thelens mount should not need adjustment. See the adapter literature for focusing directions.

WARNING

Chapter 4 Focusing 25

Imaging Field of View

When used for two-dimensional imaging applications, Princeton Instruments CCDcameras closely imitate a standard 35 mm camera. Since the CCD is not the same size asthe film plane of a 35 mm camera, the field of view at a given distance is somewhatdifferent.

D

O

B

S

ObjectLens

CCD

D = distance between the object and the CCD

B = 46.5 mm (Nikon bayonet only)

F = focal length of lens

S = horizontal or vertical dimension of CCD

O = horizontal or vertical field of view covered at a distance D

M = magnification

The field of view is:

whereO = S

M ,( )

M =FD

D – B 2

Figure 12.Imaging field

of view


Spectroscopy Systems

Focusing and Alignment of Array Detectors The detector mounting hardware provides two degrees of freedom, focus and rotation.The approach taken is to slowly move the detector in and out of focus and adjusting foroptimum while watching a live display on the monitor, followed by rotating the detectorand again adjusting for optimum. The detailed procedure follows.

1. Mount a light source such as a mercury pen-ray type in front of the entrance slit.Any light source with line output can be used. Standard fluorescent overhead lampshave good calibration lines as well. If there are no “line” sources available, it ispossible to use a broad band source such as tungsten for the alignment. If this is thecase, use a wavelength setting of 0.0nm for alignment purposes.

2. With the spectrograph properly connected to the controller, turn the power on, waitfor the spectrograph to initialize. Then set it to 435.8 nm if using a mercury lamp orto 0.0 nm if using a broadband source.

Hint: Overhead fluorescent lights produce a mercury spectrum. Use a white card tilted at45 degrees in front of the entrance slit to reflect overhead light into the spectrometer.Select 435.833 as the spectral line.

3. Set the Exposure Time of the array to a convenient value somewhere in the range of0.1 s to 1 s.

4. Set the slits to 25 µm.

5. Run the Detector in live mode and watch the display on the monitor.

Hint: If using WinView or WinSpec, simply select RUN with Freerun and asynchronoustiming (SYNCHRONOUS not selected). If using WinView/32 or WinSpec/32, selectFOCUS with Freerun and Safe Mode (asynchronous) timing selected.

6. Slowly move the detector in and out of focus. You should see the spectral line gofrom broad to narrow and back to broad. Leave the detector set for the narrowestachievable line.

Note: Focusing the detector is achieved differently on different spectrometers. Onmodels where the adapter is made of two pieces that slide together, focusing is achievedby slowly sliding the detector in and out of the exit focal plane. One-piece adapters relyon a focusing adjustment on the spectrometer. See the spectrometer manual for details.

7. Next adjust the rotation. You can do this by rotating the detector while watching alive display of the line. The line will go from broad to narrow and back to broad.Leave the detector rotation set for the narrowest achievable line.

Alternatively, take an image, display the horizontal and vertical cursor bars, andcompare the vertical bar to the line shape on the screen. Rotate the detector until theline shape on the screen is parallel with the vertical bar.

Note: When aligning other accessories, such as fibers, lenses, optical fiber adapters, firstalign the spectrograph to the slit. Then align the accessory without disturbing the detectorposition. The procedure is identical to that used to focus the spectrograph, i.e. do thefocus and alignment operations while watching a live image.

27

Appendix AOutline Drawings

Figure 13. Side-On Dewar, wide fill port


CABLE CONNECTOR

1/4� INSERTVALVE

1.50

5.00

5.00 DIA

2.06 REF

SUPERINSULATION

14.95

17.01

1.842

2.012

±.010

ELECTRONICS BOX 6.00 x 8.00

BURST DISC

Figure 14. Side-On Dewar, narrow fill port

Figure 15. End-On Dewar

29

Appendix BVacuum Restoration

Introduction All Princeton Instruments LN/CCD detectors must operate in a vacuum. A pressure of~10 mTorr is needed to prevent condensation and contaminants from collecting on theCCD, which could ruin it.

All Dewars are pumped for 72 hours at the factory while being baked at the maximumallowable temperature. This procedure removes impurities, especially water vapor, fromthe vacuum chamber. In addition, the vacuum vessel contains two traps to adsorbcontaminants over the lifetime of the Dewar (years). Finally, the Princeton Instrumentsdesign ensures trapping of any remaining contaminants on very low temperature surfacesto ensure a clean array surface.

All Dewars are helium-leak tested to ensure a total seal. The vacuum valves are of thehighest commercial vacuum grade. Each valve is individually tested and certified by themanufacturer for its vacuum integrity. As a result of the care taken to ensure vacuumquality, users can reasonably expect a long period of operation without need for concernabout the vacuum. However, it could happen that vacuum deterioration could eventuallyoccur, in which case restoring the original vacuum level would be required. If thishappens, we recommend that you contact the factory and arrange to have the unitreturned to the factory for repumping and vacuum testing.

If your facility has the necessary equipment and personnel with the necessary vacuumpumping expertise, it may be possible to repump the vacuum at your facility as describedin the following procedure.

Your vacuum system must have a trap (ideally cryogenic) placed between the detectorand the pump to prevent contamination due to backstreaming from the pump.

Note: New detectors will experience a higher outgassing rate than detectors that havebeen in operation for several months. Therefore, if a detector does not retain LN for theminimum holding time, it should be pumped.

Operating the detector without proper vacuum may cause serious or irreversible damage.Do not operate the detector unless the vacuum chamber is evacuated.

CAUTION

WARNING


Vacuum Pumpdown Procedures

Do not attempt to pump down the detector with liquid nitrogen present in the Dewar.Carefully pour out any remaining LN and wait for the detector to reach roomtemperature. Pump down according to the instructions below.

Your vacuum system must have a trap (ideally cryogenic) placed between the detectorand the pump to prevent contamination due to backstreaming from the pump.

One of two vacuum valves will be present on your Princeton Instruments brandLN-cooled detector. Because the valves are different, two separate pumpdown proceduresare provided in this section. To identify the procedure you should follow, refer to thethumbnail picture of the vacuum valve to the left of a procedure.

Procedure #1

Requirement: A laboratory-type vacuum pump capable of achieving 10 mTorr or lower.

1. Remove the Swagelok* plug on the open end of the vacuum valve. Save the plug.

2. Connect this end of the vacuum valve to the vacuum system. This is a ¼�

Swagelok connector. Do not open the vacuum valve yet.

3. Begin pumping. The vacuum equipment should first be pumped down to areasonable level before the vacuum valve is opened.

4. When a reasonable vacuum level is reached (~20 mTorr), open the vacuum valveby turning the brass knob counterclockwise a few turns.

5. If you are using a simple forepump (rotary), pump down to 5-20 mTorr. If youhave a dual pump station (e.g., forepump/diffusion pump or forepump/turbopump) pump down to 10-5 to 10-6 Torr for better performance. Initially,overnight pumping may be required to reach these levels.

6. When evacuation is complete, firmly tighten the vacuum valve by hand. Do notovertighten. The vacuum block is now sealed.

7. Remove the vacuum system from the Swagelok connector. Replace the Swagelokplug to prevent accidental loss of vacuum.

* See Appendix D for detailed information on installing Swagelok fittings.

WARNING

CAUTION

Appendix B Vacuum Restoration 31

Procedure #2

Requirement:

� A laboratory-type vacuum pump capable of achieving 10 mTorror lower.

� Special vacuum pumpdown adapter, as shown in Figure 16.To purchase this connector (PN 2550-0181) contact Customer Support.

1. Unscrew the knurled brass safety cap from the side of theDewar and set it aside.

2. Push the vacuum pumpdown adapter onto the vacuum portand tighten the brass knurled ring. The adapter should feelsnug and seated on the vacuum port.

3. Connect the vacuum system to the open tube and beginpumping. The vacuum equipment should first be pumpeddown to a reasonable level before the detector vacuum isopened.

4. After a reasonable vacuum level is reached(~20 mTorr), turn the steel vacuum pumpdown adapterknob clockwise a few turns. While holding the body ofthe adapter, pull the knob out until it stops. This actionopens the detector to the vacuum system, and a changein vacuum pressure in the system should be observed.

5. If you are using a simple forepump (rotary), pumpdown to 5-20 mTorr. If you have a dual pump station(e.g., forepump/diffusion pump or forepump/turbopump) pump down to 10-5 to 10-6 Torr for betterperformance. Initially, overnight pumping may berequired to reach these levels.

6. When this level has been achieved, push the knob allthe way in until it stops. The vacuum block is nowsealed. Turn the same knob counterclockwise severalturns, to free the plug from the vacuum connector.

7. Remove the vacuum system from the vacuumpumpdown adapter. While turning the knob counterclockwise, remove the adapterfrom the detector.

8. Screw the safety cap back on. The detector is now ready for setup.

Figure 16.Pumpdown Adapter

(PN 2550-0181)

Figure 17. Adapter mounted and connected to Vacuum System

Figure 18. Knob pulled out

33

Appendix CAutofill System

General Information

1. Dewar Adapter: ½” SAE flare nut x 3/8”Male NPT

5. Dewar Nozzle: Length to fit application x½” or 3/8” OD, with threaded male tip

2. Safety Pressure Relief Valve: 100 psi setpressure with gooseneck

6. Liquid Level Sensor: 3/8” OD Std. Xlength required.

3. Solenoid Valve: 9/32” orifice with 3/8”Female NPT, 100-120 VAC (Optional 200-240 VAC)

7. Dewar Cap Assembly

4. Vacuum Jacketed Transfer Line: 6-12 ft.Std. X ¼” ID, ¾” OD with ½” SAE flarenut on one end and integral Dewar nozzleon other end.

Figure 19. Autofill System


The Princeton Instruments brand Autofill system uses a capacitance-based method fordetermining liquid level of the LN2 in a side-looking Dewar. When the liquid goes belowthe B setpoint, the system will fill the Dewar until the A setpoint is reached. Alloperational controls for the LN2 level controller are located on the front panel of theAutofill Controller, with power, sensor, communication, and control connections at therear.

Unpacking the System1. Examine the shipping carton for any signs of damage and then check the contents. If

damage is visible, save the shipping carton and contact the factory for furtherinstructions.

2. Unpack the contents and remove all packaging materials.

3. Verify that you have received all items listed on the packing slip.

System ComponentsA typical Princeton Instruments brand autofill system has the following components:

LN-Cooled Camera ST-133 Controller

Model 186 Liquid Level Controller Sensor Assembly

Oscillator Solenoid-operated Fill Valve

Cables

Appendix C Autofill System 35

Model 186 Front and Rear Panel Controls and Connectors

Front Panel

A SETPOINTS

LENGTH

SILENCE LOWER

RAISE

LO LEVEL

INCH

CM

%

ACTIVITY

MAX

MIN

CAL

~

HI LEVEL

A

B

FILL

AUTO

OPEN

CLOSED

!

HI

BLO

INTERVAL

Model 186Liquid LevelController

2 3 4 5

111098

761

12 13 14 15

1 Fill indication LED 9 MIN calibration push-button

2 Activity LED 10 Approximate calibration push-button

3 LED display 11 MAX calibration push-button

4 HI level LED 12 Fill toggle switch

5 A level LED (control band upper limit) 13 Control mode rotary switch

6 B level LED (control band lower limit) 14 Raise/lower toggle switch

7 LO level LED 15 Units Mode toggle switch

8 Power toggle switch


Rear Panel

J2

COMMUNICATIONS

110-120 V100 V

220-240 V200 V

LINE: 50-60 Hz, 2.2A MAX

AMERICAN MAGNETICS, iNC.OAK RIDGE, TN U.S.A.

S11

ON RS-232

J8

CONTROLLER OUTPUT

!

LINE VOLTAGE, 2A MAX

1

5432

1 RS-232/422 communications port 4 Controller output receptacle tosolenoid fill valve

2 Auxiliary DB-9 connector (seeAppendix for pinout)

5 Input power connector

3 RG-59/U coaxial connector tooscillator unit via the extension cable

Setting up the SystemThe following instructions assume that a PCI card has been installed in the hostcomputer, the application software has been installed, and all cable connections for thehost computer, ST-133, and the camera have been made. The instructions also assumethat a Liquid Nitrogen supply cylinder is available.

1. Rigidly mount the camera Dewar in place to ensure that the flexible transfer line doesnot cause the Dewar to move out of position.

2. Install the sensor assembly into the camera Dewar. Be careful not to damage thesensor in any way. Dents, crimps, bends, or other physical distortions in the thin wallcapacitor will change the electrical characteristics, possibly causing calibration errorsand/or disruption of proper instrument operation.

Note: You may want to review the Calibration (page 38) and Operation (page 41)sections before installing the sensor.

3. Connect the oscillator to the cable coming from the sensor assembly. Make sure thatyou connect the cable to the correct end. Arrows on the oscillator indicate the correctorientation. You can also refer to the diagram on page 38.


Caution: Moisture or contaminants in any of the BNC coaxial connectors can shortout the sensor and cause a false ‘full’ level indication or other erroneous readings. Apack of non-conductive electrical connection lubricant (ECL or “Dielectric Tune-upGrease”) has been included with the liquid level sensor packaging to reduce thepossibility of this occurring. If desired, apply a small amount of ECL to any of theBNC connectors that may be exposed to moisture. Mate the doped connectors thenremove any excess ECL from the outside of the connector. Added protection can beachieved by covering the doped connections with a short section of heat-shrinktubing.

4. Using the J5 coaxial connector, connect the Model 186 controller to the oscillatorusing an RG-59/U coaxial cable.

5. Install the solenoid-operated fill valve by connecting the valve power cable to the ACController output receptacle on the rear panel of the Model 186. The fill valve has a9/32-inch orifice and the input and output are tapped for 3/8 NPT. Operation of thecontroller output receptacle in AUTO mode should be avoided until the controllersetpoints have been specified. See the Operation section for details on specifying thesetpoints and selecting the operational mode for the controller output receptacle.

Caution: When using the solenoid-operated control valve with the Model 186,ensure the valve is configured for the operating voltage of the Model 186. Failure todo so will result in faulty operation and may also result in valve damage.

WARNING: Before touching any of the controller output receptacle terminals ortouching the wiring connected to these terminals, remove power to the Model 186by unplugging it or turning the power switch to the off position.

The controller output receptacle conducts hazardous AC line voltage potentials. It isfor use with equipment that has no accessible live parts. Conductors connected to itsterminals must be insulated from user contact by reinforced or double insulationcapable of withstanding 4250 V (impulse) for a 240 VAC Category II installation, or2550 V (impulse) for a 120 VAC Category II installation.

This instrument is designed for operation from a single-phase power source formaximum safety. The controller output receptacle circuitry only switches the “line”(“hot”) connection to the AC mains. If two-phase power is applied, any equipmentconnected to the controller output receptacle conducts hazardous AC voltage evenwhen the controller output receptacle is not turned on.

WARNING: The Model 186 operates on 50-60 Hz power and may be configuredfor 110-120 or 208-240 VAC ±10% (100 or 200 VAC ±10% for Japan and SouthKorea). The power requirements for each controller are marked on the calibrationsticker on the bottom of the controller. Be sure your controller is configured for yourpower source prior to plugging in the line cord. Do not fail to connect the inputground terminal securely to an external earth ground.

6. Ensure the front panel switch is in the OFF position. Verify that the controller isconfigured for the proper operating voltage by referring to the calibration sticker


affixed to the bottom of the controller. If the operating voltage is correct, plug theline cord into the appropriate power receptacle.

WARNING: Do not install the Model 186 in a manner that prevents removal of theline cord from the rear panel of the controller.

J2

COMMUNICATIONS

110-120 V100 V

220-240 V200 V

LINE: 50-60 Hz, 2.2A MAX

AMERICAN MAGNETICS, iNC.OAK RIDGE, TN U.S.A.

S11

ON RS-232

J8

CONTROLLER OUTPUT

!

LINE VOLTAGE, 2A MAX

SOLENOID -OPERATEDFLOW VALVE

OUT INEXTENSION CABLERG-59/U COAXIALCABLE, 6 FT. LENGTH

REAR PANEL

OSCILLATOR

MODEL 186LIQUID LEVELCONTROLLER

OSCILLATOR CABLERG-59/U COAXIALCABLE, 6 FT. LENGTH

3/8 NPT NYLONFEED-THROUGH

SENSOR

3/8�

3/8� NPT

FRONT PANEL

TO S

ENSO

R

ACTIVESENSORLENGTH

TOTALSENSORLENGTH

A SETPOINTS

LENGTH

SILENCE LOWER

RAISE

LO LEVEL

INCH

CM

%

ACTIVITY

MAX

MIN

CAL

~

HI LEVEL

A

B

FILL

AUTO

OPEN

CLOSED

!

HI

BLO

INTERVAL

Model 186Liquid LevelController

Figure 20. Model 186 instrument, control valve and sensor system diagram


Calibration

Introduction

Model 186 controllers are calibrated at the factory for the supplied sensor. The calibrationlength and calibration liquid are listed on the calibration sticker on the bottom of thecontroller. If the factory calibration method utilized was approximate, the calibrationlength will be noted as an approximate value.

Relations between Calibration and Sensor Length

The capacitance-based method of measuring the liquid level operates by measuring thefrequency of an oscillator, which is contained in the oscillator/transmitter unit. As theliquid level varies, the value of the capacitance varies proportionally. A calibration isrequired to assure maximum accuracy for a specific sensor. The calibration MIN andMAX settings correspond to the maximum and minimum oscillation frequencies,respectively, for a given sensor configuration.

The LENGTH setting of the controller is only provided as a means of scaling the 0%(MIN) to 100% (MAX) range of the measurement to meaningful units of length. If theuser wants to operate the sensor in units of length, it will be necessary to accuratelymeasure the distance between the physical locations on the sensor corresponding to theMAX and MIN calibration points. The measured value for the length will be used inconfiguring the controller for operation.

Note: All references to “dielectric constant” herein refer to the unitless relative dielectricto �0 (�0 is the dielectric constant of a vacuum).

Calibration Procedure

Introduction

Before performing the Calibration, the MAX/MIN calibration points and the Cadj factormust be preset and the system must be fully set up so that LN can be added to the cameraDewar through the sensor assembly. Since the MAX/MIN calibration points and the Cadj

factor have been set at the factory, you do not have to reset them to perform the followingcalibration.

1. Install the sensor in the Dewar and turn on the Model 186 with the sensor connectedto the controller via the oscillator and extension cables (see the system diagram onpage 38).

2. Begin filling the Dewar. While the sensor is cooling down, there may be a slow driftin the displayed liquid level. However, when the liquid actually touches the bottom ofthe sensor, contact with the liquid surface may become apparent by virtue of morerandom and frequent fluctuations in the displayed liquid level. The liquid level tracewill also start to show an increasing profile with positive slope.

3. Once the indications of the contact between the sensor and liquid become readilyapparent, press the MIN push-button through the small hole provided in the controllerfront panel. When the calibration point has been accepted, the display will show "bbb.b"and the pushbutton can then be released. This point is the 0% level of the sensor.


Note: If the sensor is installed in the Dewar with some small amount of liquidalready in contact with the sensor, then the final MIN calibration point can be setbefore filling begins but after any thermally induced fluctuations in the observedoutput have diminished. However, note that the measured span of the liquid level isreduced by the initial level of liquid in contact with the sensor.

4. When LN vents from the Dewar, push the MAX pushbutton through the small holeprovided in the Model 186 front panel. When the calibration data has been accepted,the display will show "bbb.b" and the pushbutton can then be released. The level onthe sensor when the MAX button is pressed becomes the 100% level.

Note: If the controller displayed a 100% reading before venting occurs, then theMAX calibration point set prior to the current procedure has interfered. If this occurs,continue the liquid transfer until venting begins and then press the MAX calibrationpushbutton.

Proceed to the Operation section for directions for configuring the controller.

Resetting the MAX/MIN Calibration Points and C adj Factor

The MAX/MIN calibration points set at the factory should not need to be reset. However,if the sensor probe is slightly damaged (bent or dented), you may want to reset thesepoints to compensate for the change in capacitance. The Cadj factor would have to berecalculated if you are changing from LN to a different liquid (and vice versa).

The following procedure should be performed before installing the sensor in the targetDewar.

1. Connect the extension and oscillator cables to the J5 coaxial connector on therear panel of the controller (see page 38 for a system diagram). Do not connectthe sensor. Turn on the controller. Press the MIN push-button through the smallhole provided on the controller front panel. When the calibration point has beenaccepted, the display will show "bbb.b" and the push-button can then be released.

2. Connect the sensor to the oscillator cable (which is still connected to thecontroller via the extension cable). Press the MAX push-button through the smallhole provided on the controller front panel. When the calibration point has beenaccepted, the display will show "bbb.b" and the push-button can then be released.

3. Calculate the factor Cadj using the following equation:

where Ltotal is the total sensor length in inches, Lactive is the active sensor length ininches, and e is the dielectric constant of the target liquid.

4. Enter Cadj into the controller by placing the front panel control mode rotary switchin the SILENCE position. By using the RAISE/ LOWER toggle switch andholding it in the up or down position, adjust the displayed value up or down. Thedisplay will move slowly at first and then faster. Once near the desired value,simply release the switch momentarily and then resume changing the factor at theslower speed. Once the desired number has been reached, release the toggle switch.


5. Once the value for Cadj has been entered, momentarily press the CAL push-buttonlabeled as "~" (the tilde character) through the small hole provided in thecontroller front panel. When the value has been accepted, the display will show"ddd.d" and the button can then be released.

Operation

Turn on the Model 186

After completion of the Installation and Calibration procedures, turn on the Model 186switching the Power toggle to the POWER position. The LED display will briefly displayAAAA and then indicate the liquid level, and the yellow ACTIVITY LED will beginblinking.

Note: The ACTIVITY LED provides visual indication that the microprocessor is makingsensor readings. If a fault should develop which prohibits the microprocessor fromoperating correctly (such as a break in cabling) the LED will not blink or blink slowly,and the display will continuously show 100%.

Note: If the displayed level reading is below the LO SETPOINT level or exceeds the HISETPOINT, an audible alarm will sound. To silence the alarm, rotate the control moderotary switch on the front panel to the SILENCE position.

The controller is normally calibrated at the factory for the specific sensor supplied withthe unit for use in a target liquid. If the need arises for recalibration, see the Calibrationsection.

Active Length Setting

The Model 186 was shipped with the length value set to the active sensor length. Thissetting allows the controller to scale the measurement to meaningful units of length(inches, centimeters, or percentage) for display. To view the present length setting,switch the Units Mode toggle to either the INCH or CM position. Turn the Control Modeknob to the LENGTH position. Push and release the RAISE/ LOWER toggle either upor down. The display will momentarily show the current length setting.

To change the length setting, use the RAISE/LOWER toggle switch to move the settingup or down by continuously holding it in the up or down position. The display will moveslowly at first and then faster. Once near the desired value, simply release the switchmomentarily and then resume changing the setpoint at the slower speed. The new activesensor length is permanently stored in memory. Check the value by momentarily placingthe toggle switch in either position from the center position.

Note: The LENGTH adjustment can only be performed in the INCH or CM units modes.The LENGTH adjustment is inactive if the units are set for %.


HI and LO SETPOINTs

The HI and LO setpoints are used for alarm purposes only: they do not control filling theDewar. To adjust the HI and LO setpoints, turn the Control Mode knob to the HISETPOINT position or the LO SETPOINT position, respectively. Use theRAISE/LOWER toggle to adjust the respective setpoint in the same manner as describedfor the LENGTH adjustment. The setpoints may be located anywhere between 0% to100% of the active sensor length. The HI and LO setpoint adjustments are compatiblewith all three units modes.

a. When the measured liquid level exceeds the HI setpoint, the HI LEVEL LED onthe front panel is turned on and a set of relay contacts are closed on the 9-pin Dconnector J2 on the rear panel (see the Appendix for the pinout). When the levelreaches or falls below the HI setpoint, the LED is extinguished and the relaycontacts open.

b. When the measured liquid level falls below the LO setpoint, the LO LEVELLED on the front panel is turned on and a set of relay contacts are closed on the9-pin D connector J2 on the rear panel (see the Appendix for the pinout). Whenthe level reaches or exceeds the LO setpoint, the LED is extinguished and thecontacts open.

Notes:1. The HI and LO contacts are both closed on power-off of the controller which is a

state unique to the power-off condition.2. If the LENGTH is adjusted subsequent to configuring the various setpoints, the

percentage of active length will be maintained for all setpoints. For example, if the LENGTH is set to 100 cm and the HI SETPOINT is set to 80 cm, then adjusting the LENGTH to 150 cm will result in the HI SETPOINT being automatically scaled to 120 cm—i.e., the setting of 80% of active length is maintained.

A and B SETPOINTs

To adjust the A and B setpoints, which specify the upper and lower limits for the liquidlevel control band, turn the Control Mode knob to the A SETPOINT position or the BSETPOINT position, respectively. Use the RAISE/LOWER toggle switch to adjust therespective setpoint in the same manner as described for the LENGTH adjustment. The Aand B setpoint adjustments are compatible with all three units modes.

a. When the measured liquid level reaches or exceeds the A setpoint, the A LEVELLED on the front panel is turned on, indicating that any filling operation shouldstop. When the level falls below the A setpoint, the LED is extinguished.

b. When the measured liquid level falls below the B setpoint, the B LEVEL LED onthe front panel is turned on, indicating the filling the Dewar should start. Whenthe level reaches or exceeds the B setpoint, the LED is extinguished.

c. In addition to the LED functions, the Controller Output receptacle may be turnedon and off as discussed in the next section.

Note: The A setpoint must always be above the B setpoint. Both setpoints may be setfrom 0% to 100% of the LENGTH setting as long as A > B.


Setpoint Value

Length 9.5 in.

Cadj 150

HI 90.0%

LO 0.1%

A 80.0%

B 5.0%

Interval 10.0 min.

Table 3. Typical Values for Setpoints

Controller Output Receptacle Operational Mode

The operation of the CONTROLLER OUTPUT receptacle is controlled by the Fill toggleswitch on the front panel. Operation of the Fill toggle is as follows:

a. CLOSED (or OFF): With the controller power on and the Fill switch in theCLOSED position, the controller serves only as a level monitor, giving a levelreading on the digital display and providing data via the communication port onthe rear panel. All four setpoint LEDs (and associated J2 connector relaycontacts) operate normally; however, the Controller Output receptacle willalways be turned off.

b. OPEN (or ON): With the fill switch in the OPEN position, the rear panelController Output receptacle will be turned on, thereby starting flow if thesolenoid-operated fill valve is properly connected. The FILL LED on the frontpanel will light indicating the presence of power at the Controller Outputreceptacle. The operator is solely responsible for terminating the fill flow.

c. AUTO: With the Fill switch in the AUTO position, the Model 186 canautomatically start and stop liquid fill via the control valve, thereby maintainingthe level between the selected A and B setpoints. If the liquid level falls belowthe B setpoint, the rear panel Controller Output receptacle and front panel FILLLED are turned on. When the liquid level subsequently reaches or exceeds the Asetpoint, the Controller Output receptacle and the FILL LED are turned off.

Fill Timer INTERVAL

An INTERVAL time-out of up to 600 minutes is provided to lessen the possibility ofliquid overflow. The time-out feature is enabled when the controller is operated in theAUTO mode with an INTERVAL setting > 0. Once the liquid level falls below the Bsetpoint, an internal fill timer (whose period is the INTERVAL setting) begins to countdown. If the liquid level does not reach the A setpoint before the timer expires, thedisplay will flash rapidly and power to the rear panel Controller Output receptacle will beinterrupted. To reset this function the Fill toggle must be momentarily placed in the ONposition (to complete the filling process manually) or power to the controller must bemomentarily turned off.


Note: The INTERVAL function is disabled when the INTERVAL setting is “0.0”.Adjusting the INTERVAL setting to “0.0” will also end any in-progress functions of theINTERVAL timer.

The INTERVAL setting can be changed by turning the Control Mode knob to theINTERVAL position and using the RAISE/LOWER toggle switch to adjust the setting upor down. The display will move slowly at first and then faster. Once near the desiredvalue, which is displayed in minutes, release the switch momentarily and then continuechanging the setpoint at the slower speed. The controller is shipped from the factory witha zero interval time.

Units Display Output

Place the Units Mode toggle in the position desired for the display output units duringoperation. The % position displays the percentage of active sensor length that isimmersed in liquid.

Serial CommunicationThe 25-pin D-type connector on the rear panel of the controller is available for serialcommunications and data logger function.

Serial Port Connector and Cabling

An IBM-compatible computer’s serial port can be directly connected to the Model 186via a standard PC modem cable. Refer to your computer’s documentation to determinewhich serial ports are available on your computer and the required connector type. Thecable to connect two DB25 connectors is wired directly ( i.e., pin 1 to pin 1, pin 2 to pin2, etc.). If a DB9 connector is required at the computer interface, the connectortranslation is provided in the Appendix.

The Model 186 uses only three wires of the rear-panel DB25 connector: pin 2 (transmit),pin 3 (receive), and pin 7 (common). There is no software or hardware handshaking. TheModel 186 is classified as a DCE (Data Communication Equipment) device since ittransmits data on pin 3 and receives data on pin 2. The controller to which the Model 186is attached must do the opposite, i.e., transmit on pin 2 and receive on pin 3 (therequirements for a DTE, or Data Terminal Equipment device). If a serial-to-parallelconverter is used, it must be capable of receiving data on pin 3 or the cable connected tothe Model 186 must interchange the wires between pins 2 and 3.

The Optional RS-422 connector pinout is provided on page 50.

Command/Return Termination Characters

All commands are transmitted and received as ASCII values and are case insensitive. TheModel 186 always transmits <CR><LF> (i.e., a carriage return followed by a linefeed)at the end of a serial transmission. The Model 186 can accept <CR>, <LF> ,<CR><LF> , or <LF><CR> as termination characters from an external computer.

The simplest method for communicating with the Model 186 via RS-232 is by using theinteractive mode of a commercially available terminal emulation program. The Model186 transmits and receives information at various baud rates and uses 8 data bits, noparity, and 1 stop bit. When the Model 186 receives a terminated ASCII string, it alwayssends back a reply as soon as the string is processed. When sending commands to the


Model 186, you must wait for the reply from the Model 186 before sending anothercommand even if the reply consists of only termination characters. Otherwise, the sharedinput/output command buffer of the Model 186 may become corrupted.

Serial Communication DIP Switch Settings

The 8 DIP switches located on the rear panel of the Model 186 are used to control variousparameters of the RS-232 interface. Switches 6 through 8 control the baud rate of theinterface. Switches 3 through 5 control the time interval between data output if the datalogger function is enabled. Switch 2 controls the echo feature and Switch 1 enables thedata logger function. Each of these features is fully discussed below.

Baud Rate Control

The Model 186 baud rate is controlled by switches 6 through 8 of the communicationDIP switch on the rear panel. The unit is shipped with the baud rate set at 9600. Theswitch settings for various baud rates are (on = 1 or the up position):

DIP switch

6 7 8 Baud rate

off off off 300

off off on 600

off on off 1200

off on on 2400

on off off 4800

on off on 9600

Echo Function

The Model 186 has an echo feature that is enabled or disabled by communication DIPswitch 2. When the echo function is enabled, the Model 186 will echo the incomingcommand characters back to the transmitting device. The echo feature is useful whenusing an interactive terminal program on a host computer for communicating with theModel 186. The settings are:

DIP switch 2 Function

on Echo On

off Echo Off

Data Logger Function

Switch 1 of the communications DIP switch controls the data logger function. The unit isshipped with the data logger function disabled. This feature is normally used with a


printer rather than a host computer, since a computer can be more usefully programmedutilizing the available command set. The data logger function generates a time relative tocontroller power-up and a corresponding level. The units of the level output are set by theUnits Mode toggle switch. The time and corresponding level are formatted and output tothe host device at regular intervals as specified by the switches 3 through 5. The settingsfor the data logger function are:

DIP switch 1 Function

on Data Logger On

off Data Logger Off

The host device can be a standard dot matrix printer connected via a serial-to-parallelconverter, or connected directly with a printer capable of receiving serial data.Presumably, any serial-to-parallel converter which can be properly configured isacceptable. The Model 186 has been tested with a standard, low cost converterconfigured as a DTE device, 8 data bits, no parity, and 1 stop bit. In order tocommunicate with the host device, it is necessary to set the Model 186 to the identicalbaud rate of the host device.

Data Logger Output Interval

The interval between successive output from the data logger function is controlled byswitches 3 through 5. The unit is shipped with the data logger function disabled (see above).The available intervals and the corresponding switch settings are (on = 1 or the up position):

DIP switch

3 4 5 Interval (minutes)

off off off 1

off off on 2

off on off 5

off on on 10

on off off 20

on off on 30

on on off 60

Serial Command Set Reference

All commands sent to the Model 186 are processed and the Model 186 responds with areturn value (if applicable) and termination. All return values are terminated with<CR><LF> (i.e., a carriage return followed by a linefeed). For those commands that donot return a value, the Model 186 will return the <CR><LF> termination only.

Commands for Controlling the Units of Measurement

The CM command sets the units of measurement to centimeters and the INCH commandselects inches. The PERCENT command sets the units of measurement to the percentage


of active sensor length that is immersed in liquid. The units of measurement selectedthrough the serial interface are controlled independently from the Units Modetoggle switch used for controlling the front panel display. The remote units setting issaved in permanent memory by the SAVE command and is restored at power-up. TheUNIT command returns a one character value (and termination) indicating the currentunits—C for centimeters, I for inches, or % for percentage.

Command: CM Function: Sets the units ofmeasurement tocentimeters

Returns: <CR><LF>

Command: INCH Function: Sets the units ofmeasurement toinches

Returns: <CR><LF>

Command: PERCENT Function: Sets themeasurement to %of sensor length

Returns: <CR><LF>

Command: UNIT Function: Returns the currentunits in use

Returns: C, I, or %<CR><LF>

Commands for Configuring Permanent Memory

Command: HI= <value> Function: Configures the HIsetpoint limit

Returns: <CR><LF>

Command: LO= <value> Function: Configures the LOsetpoint limit

Returns: <CR><LF>

Command: A= <value> Function: Configures the Asetpoint (controlband upper limit)

Returns: <CR><LF>

Command: B= <value> Function: Configures the Bsetpoint (controlband lower limit)

Returns: <CR><LF>

Command: INTERVAL=<value>

Function: Configures the filltimer in minutes

Returns: <CR><LF>

Command: LENGTH=<value>

Function: Configures theactive sensorlength

Returns: <CR><LF>

Command: SAVE Function: Saves theconfiguration topermanent memory

Returns: <CR><LF>


The HI and LO command configure the high and low setpoint limit values respectively.For example, HI=90.0 would configure the high setpoint limit to 90.0 in whichever unitsof measurement last selected through the serial interface. The A and B commandsconfigure the upper limit and lower limit of the control band, respectively. The HI, LO,A, and B commands are compatible with the percent units selection.

The LENGTH command configures the active sensor length setting in the current units.LENGTH=35.0 would configure the active sensor length to 35.0 units of centimeters orinches.

Note: The LENGTH=<value> command will only function if CM or INCH are currentlyselected as the units of measurement. The LENGTH command does not configure theModel 186 if the units of measurement are PERCENT.

The INTERVAL command sets the fill timer in minutes as described in the Operationsection on page 41. Setting the value of INTERVAL to 0 disables the fill timer function.

The SAVE command saves the HI, LO, A, B, INTERVAL, LENGTH, and currentremote units settings to permanent memory. Saved settings are then recalled each timethe power is turned off and then reapplied to the controller. If the configuration ischanged from the front panel, the new settings are automatically saved to permanentmemory.

Commands for Querying the Configuration

The HI, LO, A, B, INTERVAL, and LENGTH commands return the currentconfiguration of the controller. Each return value is terminated with <CR><LF>.

Command: HI Function: Returns the HIsetpoint limit in thecurrent units

Returns: <value><CR><LF>

Command: LO Function: Returns the LOsetpoint limit in thecurrent units


Command: A Function: Returns the Asetpoint limit in thecurrent units


Command: B Function: Returns the Bsetpoint limit in thecurrent units


Command: INTERVAL Function: Returns the filltimer setting inminutes


Command: LENGTH Function: Returns the activesensor length in thecurrent units



Command for Returning a Level Measurement

Command: LEVEL Function: Returns the liquidlevel in the currentunits


The LEVEL command returns the liquid level in the current units selected through thecommunication interface.

Commands for Performing Remote Calibration

The calibration commands perform a remote calibration equivalent to activating the frontpanel MIN, MAX, and “~” (approximate) calibration buttons. The calibration isautomatically saved to permanent memory. See the Calibration section for moreinformation regarding calibration.

Command: MINCAL Function: Performs a MINcalibration

Returns: <CR><LF>

Command: MAXCAL Function: Performs a MAXcalibration

Returns: <CR><LF>

Command: APPROX=<value>

Function: Performs anapproximatecalibration usingvalue as theapproximatecalibration factor

Returns: <CR><LF>0RGHO___

J2 Connector Pinout

Pin Function

1 Not used

2 Not used

3 Not used

4 Not used

5 & 6 LO level relay contacts (dry)

7 & 8 HI level relay contacts (dry)

9 Not used

The HI level and LO level contacts are provided for external use by the customer. Whena HI or LO level condition exists, the respective contact pairs are closed. All setpointshave 1/2 mm hysteresis, therefore the respective contact pairs may “chatter” if the liquidsloshes, bubbles, etc.


The HI level and LO level contacts also provide positive indication of a power-offcondition. With a power-off condition, both the HI level and LO level contacts will beclosed, which is a state unique to the power-off condition.

The following table provides the specifications for the relay contacts:

Max switching VA 10

Max switching voltage 30 VAC or 60 VDC

Max switching current 0.5 A

Max continuous current 1.5 A

RS-232 Cable DB-25 to DB-9 Translation

DB-25 Pin DB-9 Pin

2 3

3 2

4 7

5 8

6 6

7 5

All other pins on the DB-25 connector are unused.This is standard PC modem cable wiring.

8 1

20 4

22 9

RS-422 Cable Wiring


Dielectric Constants for Common LiquidsThe table below contains relative dielectric constants for several common liquids atatmospheric pressure (unless otherwise noted).

Liquid Dielectric Constant *

Argon (A) 1.53 @ -191°C

Carbon dioxide (CO2 ) 1.60 @ 20°C, 50 atm

Hydrogen (H2 ) 1.228 @ 20.4 K

Methane (CH4 ) 1.70 @ -173°C

Nitrogen (N2 ) 1.454 @ -203°C

Propane (C3 H8 ) 1.61 @ 0°C

Oxygen (O2 ) 1.507 @ -193°C

TroubleshootingThe following paragraphs serve as an aid to assist a qualified service person (QSP) introubleshooting a potential problem with the Model 186. If the QSP is not comfortablewith troubleshooting the system, you may contact an authorized Roper ScientificTechnical Support Representative for assistance. Refer to “Additional Technical Support”on page 54.

This controller contains CMOS components that are susceptible to damage byElectrostatic Discharge (ESD). Take the following precautions whenever the cover of thecontroller is removed.

1. Disassemble the controller only in a static-free work area.

2. Use a conductive workstation or work area to dissipate static charge.

3. Use a high resistance grounding wrist strap to reduce static charge accumulation.

4. Ensure all plastic, paper, vinyl, Styrofoam ® and other static generating materialsare kept away from the work area.

5. Minimize the handling of the controller and all static sensitive components.

6. Keep replacement parts in static-free packaging.

7. Do not slide static-sensitive devices over any surface.

8. Use only antistatic type solder suckers.

9. Use only grounded-tip soldering irons.

* Reference: Weast, Robert C. Ph.D., Editor, CRC Handbook of Chemistry and Physics 67thEdition, CRC Press, Inc., Boca Raton, FL, 1986 (pgs. E-49 through E-53).

Table 4. Dielectric Constants for Common Liquids


No level reading

1. Ensure that the controller is connected to a power source of proper voltage.

WARNING: If the controller has been found to have been connected to an incorrectpower source, return the controller to Roper Scientific for evaluation to determine theextent of the damage. Frequently, damage of this kind is not visible and must bedetermined using test equipment. Connecting the controller to an incorrect power sourcecould damage the internal insulation and/or the ground requirements, thereby, possiblypresenting a severe life-threatening electrical hazard.

2. Verify continuity of the line fuse, F1, located on the controller printed circuit board.

WARNING: This procedure is to be performed only when the controller is completelyturned off by removing the powercord from the power receptacle. Failure to do so couldresult in personnel coming in contact with high voltages capable of producing life-threatening electrical shock.

a. Ensure the controller is completely turned off by disconnecting the powercordfrom the power source. Disconnect the powercord from the connector locatedon the rear panel of the controller.

b. Remove the controller top cover and check the fuse F1 for continuity.

c. If the fuse is bad, replace with a 315 mA IEC 127-2 Type F Sheet II 5x20mmfuse.

CAUTION: Installing fuses of incorrect values and ratings could result in damage to thecontroller in the event of component failure.

d. Replace the fuse and securely fasten the controller top cover. Reconnect thepowercord.

3. Verify the input voltage selector switch on the controller’s printed circuit board isin the proper position for the available power receptacle at the customer’sfacility. Checking the input voltage selector requires removal of the top cover ofthe controller. Observe the same safety procedures as presented in step 2.

Erratic or erroneous level reading

1. Verify that the sensor is properly connected to the oscillator cable and theextension cable (see the system diagram on page 38).

2. Verify the cabling has no breaks or cuts.

3. If the Model 186 suddenly reads 100% without a corresponding level, there is apossibility of moisture in the connector at the top of the sensor. Disconnect theBNC connection and remove any moisture. Moisture or contaminants in any ofthe BNC coaxial connectors can short out the sensor and cause a false ‘full’ levelindication or other erroneous readings. A pack of non-conductive electricalconnection lubricant (ECL or “Dielectric Tune-up Grease”) has been includedwith the liquid level sensor packaging to reduce the possibility of this occurring.Apply a small amount of ECL to any of the BNC connectors that may be exposedto moisture. Mate the doped connectors then remove any excess ECL from the


outside of the connector. Added protection can be achieved by covering thedoped connections with a short section of heat-shrink tubing.

Note: MSDS sheets for the ECL are available upon request.

4. Ensure the oscillator unit is not exposed to large temperature gradients such asthose that occur near Dewar vents. Extreme temperature changes of the oscillatorunit can cause readout errors.

5. Rapidly varying or sloshing liquids will sometimes make one think the controlleris in error when it is actually operating properly.

6. Capacitance-based sensors used in cryogenic liquid systems are sometimesexposed to humidified air when the cryogenic vessel is emptied. This oftenhappens when a cold trap runs out of liquid. As the sensor warms, the electronicscan show large errors (readings greater than 20% are not uncommon). This is dueto the fact that air contains moisture which will condense between the coldsensing tubes. This small film of moisture can cause a shorted or partially shortedcondition. The electronics may recognize this as a higher level reading anddisplay some positive level. As the sensor warms over some period of time, themoisture can evaporate and the sensor will again approach the correct reading of0%. This condition can also be corrected immediately if liquid nitrogen is addedto the cold trap freezing the residual moisture. This is a physical phenomenonand does not indicate any problem with your Roper Scientific level equipment.

7. Verify the sensor is free of contaminants and not subject to any physicaldistortion. Disconnect the BNC connector at the top of the sensor and measurethe sensor resistance by placing an ohmmeter across the center pin and the outerbarrel of the connector. The resistance of the sensor should typically be >10 M��

Controller output does not turn on

WARNING: This procedure is to be performed only when the controller is completelyturned off and the power-cord has been removed from the power receptacle. Failure to doso could result in personnel coming in contact with high voltages capable of producinglife-threatening electrical shock.

1. Verify continuity of controller output fuses, F2 and F3, located on the controllerprinted circuit board.

a. Ensure the controller is turned off and that the powercord is disconnected fromthe power source. Disconnect the powercord from the connector located on therear panel of the controller.

b. Remove the controller top cover and check the fuses F2 and F3 for continuity.

c. If a fuse is bad, replace with a 2.5A IEC 127-2 Type F Sheet II 5x20mm fuse.

d. Check your connected equipment for compliance with the output receptaclerating.

CAUTION: Installing fuses of incorrect values and ratings could result in damage to thecontroller in the event of component failure.

2. Replace the fuse and securely fasten the controller top cover. Reconnect thepowercord.


Unit not responding to communications

1. Verify your communications cable integrity and wiring. See page 50 for theDB-25 to DB-9 translation for RS-232 cables.

2. Check to make sure you are sending the correct termination to the controller.Make sure the echo feature is set correctly for your application and the baud ratematches the setting of the host device. Check your host communications softwareand make sure it is recognizing the return termination characters from thecontroller. For serial communication, the return termination characters are<CR><LF>.

3. If the controller is responding repeatedly with -8 as the return message, try adevice clear command (DCL) or powering the controller off and then back on. Besure you are sending valid commands.

Custom Instrument ConfigurationsModifying the line voltage requirements

WARNING: Before removing the cover of the controller, remove the power from thecontroller by disconnecting the powercord from the power receptacle. Failure to do thiscould expose the user to high voltages and could result in life-threatening electricalshock.

CAUTION: The Model 186 controller operates on 50-60 Hz power and may beconfigured for 110-120 or 208-240 VAC ±10% (100 or 200VAC ±10% for Japan andSouth Korea). The power requirements for each controller are marked on the rear panel.Be sure the controller’s power requirements match your power source prior to pluggingin the line cord. Do not fail to connect the input ground terminal securely to an externalearth ground.

If the controller operating voltage needs to be changed, make sure the controller is turnedoff and that the powercord is disconnected from the power source. Remove the controllercover and slide the voltage selector switch on the main printed circuit board to the propervoltage. Replace the controller cover and indelibly mark the rear panel indications tomatch the new configuration.

Additional Technical SupportIf the cause of a problem cannot be located, contact a Roper Scientific representative at(609) 587-9797 for assistance. The Roper Scientific technical support group may also bereached by Internet e-mail at [email protected]. Additional technicalinformation, latest software releases, etc. are available at the Roper Scientific WorldWide Web site at: http://www.roperscientific.com

Do not return the Model 186 or other liquid level system components to Roper Scientificwithout prior return authorization.


Return Authorization

Items to be returned to Roper Scientific for repair (warranty or otherwise) require a returnauthorization number to ensure your order will receive proper attention. Please call aRoper Scientific representative at (609) 587-9797 for a return authorization numberbefore shipping any item back to the factory.

Specifications

Level Measurements a

Resolution: 0.1%, 0.1 cm, or 0.1 in

Linearity: �0.1%

Maximum Length Readout: 650.0 cm (255.9 in)

Operating ParametersHI and LO Alarms: 0% to 100% adjustable

HI/LO Alarm Relay Contact Ratings: 10 VA, 30 VAC or 60 VDC, 0.5 A (normallyopen, closed on alarm)

A and B Control Setpoints: 0% to 100% adjustable

Controller Output: AC line voltage @ 2A max current

Fill Timer: 0.1 to 600.0 minutes

Power RequirementsPrimary bb.: 110-120 or 208-240 VAC �10% 50 - 60 Hz

For Japan or S. Korea: 100 or 200 VAC �10%

Maximum Current: 2.2 A

PhysicalDimensions (Standard): 97 mm H x 213 mm W x 282 mm D (3.8" H x 8.4" W x

11.1" D)

Weight (Standard): 1.6 kg (3.6 lbs.)

EnvironmentalAmbient Temperature: Operating: 0 °C to 50 °C (32 °F to 122 °F)

Nonoperating: -20 °C to 60 °C (-4 °F to 140 °F)

a. Under extreme radiated electromagnetic field conditions (3V/m at 450 MHz to 610 MHz), the accuracymay be degraded by an additional �0.7%.

b. Units configured for Japan or South Korea cannot be configured for operation at other voltages withoutan internal transformer change, and vice versa.

57

Appendix DSwagelok Fittings

InstallationSwagelok Tube Fittings come completely assembled, finger-tight, and are ready forimmediate use. Disassembly before use is unnecessary and could result in dirt or foreignmaterial getting into the fitting and causing leaks.

Swagelok Tube Fittings are installed in three (3) easy steps, as follows.

Step 1Simply insert the tubing into the Swagelok TubeFitting. Make sure that the tubing rests firmly onthe shoulder of the fitting and that the nut isfinger-tight.

Step 2Before tightening the Swagelok nut, scribe thenut at the 6 o’clock position.

Step 3Hold the fitting body steady with a backupwrench and tighten this nut 1¼ turns. Watch thescribe mark, making one complete revolutionand continue to the 9 o’clock position.

By scribing the nut at the 6 o’clockposition as it appears to you, there willbe no doubt as to the starting position.When the nut is tightened 1¼ turns tothe 9 o’clock position, you can easilysee that the fitting has been properlytightened.

Use of the Gap Inspection Gauge (1¼turns from finger-tight) ensuressufficient pull-up.

Notes:

For 1/16�, 1/8�, 3/16�, 2 mm, 3 mm and 4 mmsize tube fittings, only ¾ turn from finger tight isnecessary.

A Swagelok Hydraulic Swaging unit must beused for assembly of Swagelok Tube Fittingsonto 1¼�, 1½�, 2�, 28 mm, 32 mm, and 38 mmoutside diameter steel and stainless steel tubing.


High Pressure Applicationsor High-Safety-Factor Systems

Due to variations in tubing diameters, a common starting point is desirable. Using awrench, tighten the nut to the SNUG position. Snug is determined by tightening the nutuntil the tubing will not rotate freely (by hand) in the fitting. If tube rotation is notpossible, tighten the nut approximately 1/8 turn from the finger-tight position. At thispoint, scribe the nut at the 6 o’clock position and tighten the nut 1¼ turns. The fitting willnow hold pressures well above the rated working pressure of the tubing.

Retightening InstructionConnections can be disconnected and retightened many times. The same reliable leak-proof seal can be obtained every time the connection is remade. Directions follow.

Fitting shown in the disconnected position.

Insert tubing with preswaged ferrules intofitting body until front ferrule seats.

Tighten nut by hand. Rotate nut to theoriginal position with a wrench. An increasein resistance will be encountered at theoriginal position.

Then tighten slightly with the wrench. Smaller tube sizes will take less tightening toreach the original position, while larger tube sizes will require more tightening. The wallthickness will also have an effect on tightening.

DECLARATION OF CONFORMITY

We,

ROPER SCIENTIFIC(PRINCETON INSTRUMENTS)

3660 QUAKERBRIDGE ROAD

TRENTON, NJ 08619

Declare under our sole responsibility, that the product

ST-133A CONTROLLER w/LN CAMERA HEAD

To which this declaration relates, is in conformity with general safety requirement for electricalequipment standards:

IEC 1010-1:1990, EN 61010-1:1993/A2:1995

EN 61326 for Class A, 1998,

(EN 61000-4-2, EN 61000-4-3, EN 61000-4-4, EN 61000-4-5,EN 61000-4-6, EN 61000-4-11)

Which follow the provisions of the

CE LOW VOLTAGE DIRECTIVE 73/23/EEC.

And

EMC DIRECTIVE 89/336/EEC.

Date: August 7, 2002TRENTON, NJ (PAUL HEAVENER)

Engineering Manager

61

Warranty & Service Limited Warranty: Roper Scientific Analytical Instrumentation

Roper Scientific, Inc. ("Roper Scientific," us," "we," "our") makes the following limited warranties. These limited warranties extend to the original purchaser ("You", "you") only and no other purchaser or transferee. We have complete control over all warranties and may alter or terminate any or all warranties at any time we deem necessary.

Basic Limited One (1) Year Warranty Roper Scientific warrants this product against substantial defects in materials and / or workmanship for a period of up to one (1) year after shipment. During this period, Roper Scientific will repair the product or, at its sole option, repair or replace any defective part without charge to you. You must deliver the entire product to the Roper Scientific factory or, at our option, to a factory-authorized service center. You are responsible for the shipping costs to return the product. International customers should contact their local Roper Scientific authorized representative/distributor for repair information and assistance, or visit our technical support page at www.roperscientific.com.

Limited One (1) Year Warranty on Refurbished or Discontinued Products Roper Scientific warrants, with the exception of the CCD imaging device (which carries NO WARRANTIES EXPRESS OR IMPLIED), this product against defects in materials or workmanship for a period of up to one (1) year after shipment. During this period, Roper Scientific will repair or replace, at its sole option, any defective parts, without charge to you. You must deliver the entire product to the Roper Scientific factory or, at our option, a factory-authorized service center. You are responsible for the shipping costs to return the product to Roper Scientific. International customers should contact their local Roper Scientific representative/distributor for repair information and assistance or visit our technical support page at www.roperscientific.com.

Normal Wear Item Disclaimer Roper Scientific does not warrant certain items against defect due to normal wear and tear. These items include internal and external shutters, cables, and connectors. These items carry no warranty, expressed or implied.

VersArray (XP) Vacuum Chamber Limited Lifetime Warranty Roper Scientific warrants that the cooling performance of the system will meet our specifications over the lifetime of the VersArray (XP) detector or Roper Scientific will, at its sole option, repair or replace any vacuum chamber components necessary to restore the cooling performance back to the original specifications at no cost to the original purchaser. Any failure to "cool to spec" beyond our Basic (1) year limited warranty from date of shipment, due to a non-vacuum-related component failure (e.g., any components that are electrical/electronic) is NOT covered and carries NO WARRANTIES EXPRESSED OR IMPLIED. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.


Sealed Chamber Integrity Limited 24 Month Warranty Roper Scientific warrants the sealed chamber integrity of all our products for a period of twenty-four (24) months after shipment. If, at anytime within twenty-four (24) months from the date of delivery, the detector should experience a sealed chamber failure, all parts and labor needed to restore the chamber seal will be covered by us. Open chamber products carry NO WARRANTY TO THE CCD IMAGING DEVICE, EXPRESSED OR IMPLIED. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Vacuum Integrity Limited 24 Month Warranty Roper Scientific warrants the vacuum integrity of all our products for a period of up to twenty-four (24) months from the date of shipment. We warrant that the detector head will maintain the factory-set operating temperature without the requirement for customer pumping. Should the detector experience a Vacuum Integrity failure at anytime within twenty-four (24) months from the date of delivery all parts and labor needed to restore the vacuum integrity will be covered by us. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Image Intensifier Detector Limited One Year Warranty All image intensifier products are inherently susceptible to Phosphor and/or Photocathode burn (physical damage) when exposed to high intensity light. Roper Scientific warrants, with the exception of image intensifier products that are found to have Phosphor and/or Photocathode burn damage (which carry NO WARRANTIES EXPRESSED OR IMPLIED), all image intensifier products for a period of one (1) year after shipment. See additional Limited One (1) year Warranty terms and conditions above, which apply to this warranty. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

X-Ray Detector Limited One Year Warranty Roper Scientific warrants, with the exception of CCD imaging device and fiber optic assembly damage due to X-rays (which carry NO WARRANTIES EXPRESSED OR IMPLIED), all X-ray products for one (1) year after shipment. See additional Basic Limited One (1) year Warranty terms and conditions above, which apply to this warranty. Responsibility for shipping charges is as described above under our Basic Limited One (1) Year Warranty.

Software Limited Warranty Roper Scientific warrants all of our manufactured software discs to be free from substantial defects in materials and / or workmanship under normal use for a period of one (1) year from shipment. Roper Scientific does not warrant that the function of the software will meet your requirements or that operation will be uninterrupted or error free. You assume responsibility for selecting the software to achieve your intended results and for the use and results obtained from the software. In addition, during the one (1) year limited warranty. The original purchaser is entitled to receive free version upgrades. Version upgrades supplied free of charge will be in the form of a download from the Internet. Those customers who do not have access to the Internet may obtain the version upgrades on a CD-ROM from our factory for an incidental shipping and handling charge. See Item 12 in the following section of this warranty ("Your Responsibility") for more information.

Warranty & Service 63

Owner's Manual and Troubleshooting You should read the owner’s manual thoroughly before operating this product. In the unlikely event that you should encounter difficulty operating this product, the owner’s manual should be consulted before contacting the Roper Scientific technical support staff or authorized service representative for assistance. If you have consulted the owner's manual and the problem still persists, please contact the Roper Scientific technical support staff or our authorized service representative. See Item 12 in the following section of this warranty ("Your Responsibility") for more information.

Your Responsibility The above Limited Warranties are subject to the following terms and conditions:

1. You must retain your bill of sale (invoice) and present it upon request for service and repairs or provide other proof of purchase satisfactory to Roper Scientific.

2. You must notify the Roper Scientific factory service center within (30) days after you have taken delivery of a product or part that you believe to be defective. With the exception of customers who claim a "technical issue" with the operation of the product or part, all invoices must be paid in full in accordance with the terms of sale. Failure to pay invoices when due may result in the interruption and/or cancellation of your one (1) year limited warranty and/or any other warranty, expressed or implied.

3. All warranty service must be made by the Roper Scientific factory or, at our option, an authorized service center.

4. Before products or parts can be returned for service you must contact the Roper Scientific factory and receive a return authorization number (RMA). Products or parts returned for service without a return authorization evidenced by an RMA will be sent back freight collect.

5. These warranties are effective only if purchased from the Roper Scientific factory or one of our authorized manufacturer's representatives or distributors.

6. Unless specified in the original purchase agreement, Roper Scientific is not responsible for installation, setup, or disassembly at the customer’s location.

7. Warranties extend only to defects in materials or workmanship as limited above and do not extend to any product or part which has: • been lost or discarded by you; • been damaged as a result of misuse, improper installation, faulty or

inadequate maintenance or failure to follow instructions furnished by us; • had serial numbers removed, altered, defaced, or rendered illegible; • been subjected to improper or unauthorized repair; or • been damaged due to fire, flood, radiation, or other "acts of God" or other

contingencies beyond the control of Roper Scientific. 8. After the warranty period has expired, you may contact the Roper Scientific

factory or a Roper Scientific-authorized representative for repair information and/or extended warranty plans.

9. Physically damaged units or units that have been modified are not acceptable for repair in or out of warranty and will be returned as received.

10. All warranties implied by state law or non-U.S. laws, including the implied warranties of merchantability and fitness for a particular purpose, are expressly limited to the duration of the limited warranties set forth above. With the exception of any warranties implied by state law or non-U.S. laws, as hereby limited, the forgoing warranty is exclusive and in lieu of all other warranties, guarantees, agreements, and similar obligations of manufacturer or seller with respect to the repair or replacement of any parts. In no event shall Roper Scientific’s liability exceed the cost of the repair or replacement of the defective product or part.

11. This limited warranty gives you specific legal rights and you may also have other rights that may vary from state to state and from country to country. Some states and countries do not allow limitations on how long an implied warranty lasts, when an action may be brought, or the exclusion or limitation of incidental or consequential damages, so the above provisions may not apply to you.

12. When contacting us for technical support or service assistance, please refer to the Roper Scientific factory of purchase, contact your authorized Roper Scientific representative or reseller, or visit our technical support page at www.roperscientific.com.

Contact Information Roper Scientific's manufacturing facility for this product is located at the following address:

Roper Scientific 3660 Quakerbridge Road Trenton, NJ 08619 (USA)

Tel: 800-874-9789 / 609-587-9797 Fax: 609-587-1970

Technical Support E-mail: [email protected]

For technical support and service outside the United States, see our web page at www.roperscientific.com. An up-to-date list of addresses, telephone numbers, and e-mail addresses of Roper Scientific's overseas offices and representatives is maintained on the web page.


65

IndexA/B setpoints, 42

controller output, 43Fill LED, 43

Accessoriesalignment of, 26

Activity LED, 35, 41AR-coatings, 9Array, 9Audible alarm, 41Autofill system, 33Baseline, 23Baud rate control, 45Cable

detector, 11Calibration

closed Dewar, 39presetting MAX/MIN points, 40remote commands, 49suitable light sources, 26

Capacitance, 39Cautions

need for trap in vacuum system, 30Commands - serial communication, 46Configuration

A/B setpoints, 42controller output mode, 43fill timer, 43HI setpoint, 42LO setpoint, 42units mode, 44

Connector - J2 pinout, 49Contact information, 54, 64Controller output

A/B setpoints, 43mode, 43

Data logger - serial communication, 45DB-25 to DB-9 translation, 50Detectors

focusing and alignment, 26rotation of, 26

Dewar, 9, 20, 29DIP switch settings, 45Echo - serial communication, 45EEV, 13Electrical connection lubricant (ECL), 37ESD precautions, 51Field of view, 25Fill LED, 43Fill timer, 43Focusing, 23

Focusing and Alignment, 26Frost, 20HI Level LED, 42HI setpoint, 42

J2 - pins 7&8, 42HI/LO contacts specifications, 50Holding times, 17Ice buildup, 20Indicator

TEMP LOCK, 18Interactive communication, 44Interval timeout, 43Lenses, 11LN, 20LO Level LED, 42LO setpoint, 42

J2 - pins 5&6, 42Method of measurement, 39Outgassing, 29Overexposure, 12, 15Remote calibration, 49Return authorization, 55Serial communication

Baud rate, 45command set, 46data logger, 45DIP switch settings, 45echo function, 45interactive communication, 44remote calibration, 49termination characters, 44

Serial port connector/cables, 44Shutter, 9, 24

entrance slit, 14Spectrometer

Acton, 13Chromex 250IS, 13deep focal plane, 13ISA HR320, 13ISA HR640, 13shallow focal plane, 13

Spectrometer mounting, 12Technical support, 54, 64TEK, 13TEMP LOCK indicator, 18Temperature control

introduction to, 18Temperature lock, 18Termination characters, 44


Trap, 29vacuum, 30

Troubleshootingchecking communications setup, 54contacting customer support, 54controller responds with -8, 54erratic display, 52no controller output, 53no level reading, 52power LED off, 52replacing the fuse, 52

Units Moderemote commands, 46toggle switch, 35, 44

UV scintillator, 7Vacuum

pumping, 30

Vacuum repumpingrequired equipment

lab-type vacuum pump, 30, 31trap to prevent contaminant

backstreaming, 30Warranties, 61

image intensifier detector, 62one year, 61owner's manual and troubleshooting, 63refurbished/discontinued products, 61

shutter, 61software, 63vacuum integrity, 62VersArray (XP) vacuum chamber, 62

sealed chamber, 62

x-ray detector, 62your responsibility, 63

Windowsdetector, 9

ln/ccd detector manualevryan/mro/pi1k/ln-ccd detector manual.pdf12 ln/ccd detector manual version...

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