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Instruction Manual
This manual contains complete instructions for setting up and using
the MA235 ion analyzer. Applications information is also available.
The information contained in this manual was correct at the time of going to print. However, we continue to improve products and reserve
the right to change specifications, equipment and maintenanceprocedures at any time.
This manual is copyrighted, and all rights are reserved. No part of
this manual may be reproduced by any means or in any form withoutprior consent in writing.
The power supply unit is classed as IEC Class II equipment (equipment
providing an adequate degree of protection against electric shocks, inwhich additional safety precautions, for example, double or reinforced
insulation, are included). The MA235 is intended for use by personsknowledgeable in safe laboratory practices. If the MA235 is not usedin accordance with these instructions for use, the protection provided
by the equipment may be impaired.
The MA235 is suitable for direct current only.
This equipment generates, uses and can radiate radio frequencyenergy and if not installed and used in accordance with the instruc-tion manual, may cause interference with radio communications. Ithas been tested and found to comply with the limits for a Class A computing device pursuant to Subpart J of Part 15 of FCC Rules,
which are designed to provide reasonable protection against suchinterference when operated in a commercial environment. Operationof this equipment in a residential area is likely to cause interferencein which case the user at his own expense will be required to takewhatever measures may be required to correct the interference.
There are no user replaceable parts in the MA235 or power supplyunit. Do not remove the covers.
FS 981/SM 1746
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Contents
1 Set Up
1.1 Unpacking and Installation ................................................ 5 1.2 Input and Output Connections ........................................... 6 1.3 Controls ............................................................................. 7
2 Operation
2.1 pH Measurements ............................................................. 8 2.1.1 Calibrating a pH Electrode ................................................ 8
2.2 mV Measurements .......................................................... 10 2.2.1 Relative mV Measurements ............................................ 10
2.3 Concentration Measurements ......................................... 112.3.1 Calibrating an Ion Selective Electrode ............................ 11
2.4 Known Addition/Subtraction Measurements ................... 13
2.5 Sample Addition/Subtraction Measurements .................. 14
2.6 Temperature Measurements ........................................... 15
2.7 Manual and Auto Endpoint, and Endpoint Time ............. 15 2.8 Sample ID ........................................................................ 16
2.9 Program Menu ................................................................. 17
2.10 Calibration Programming................................................. 19 2.10.1 Calibration Point Setting .................................................. 19 2.10.2 Last Calibration Recall .................................................... 20 2.10.3 mV Offset Setting ............................................................ 212.10.4 Isopotential Point Setting (pH) ........................................ 21
2.11 Display Menu ................................................................... 22 2.11.1 Measurement Channel Selection .................................... 22 2.11.2 Units for Measurement Selection .................................... 22 2.11.3 Display Resolution for pH Selection ................................ 23
2.12 System 1 Menu ................................................................ 26 2.12.1 Time and Date Setting ..................................................... 24 2.12.2 Language Selection ......................................................... 24 2.12.3 Baud Rate Selection ........................................................ 25
2.12.4 Key Press Beeper Setting ............................................... 25
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Contents (cont)
2 Operation (cont)
2.13 System 2 Menu ................................................................ 26 2.13.1 Temperature Mode Selection .......................................... 26 2.13.2 Manual Temperature Setting ........................................... 26
2.13.3 Endpoint Time Setting ..................................................... 27 2.13.4 Meter Self Test ................................................................ 27
2.14 Limits Menu ..................................................................... 29
2.14.1 Alarm Option Selection .................................................... 29 2.14.2 High/Low Limits for pH .................................................... 30
2.14.3 High/Low Limits for Temperature .................................... 30 2.14.4 High/Low Limits for pH Electrode Slope.......................... 31
2.15 Datalog Menu .................................................................. 32 2.15.1 Datalog Selection ............................................................ 32 2.15.2 Interval Timer Setting ...................................................... 32 2.15.3 Recalling Data ................................................................. 33 2.15.4 Clearing Data ................................................................... 34
2.16 GLP Menu........................................................................ 35
2.16.1 GLP Option Selection ...................................................... 35 2.16.2 Cal Alarm Setting............................................................. 35 2.16.3 Entering ID Number ......................................................... 36
2.17 Method Menu ................................................................... 37 2.17.1 Method Saving ................................................................. 37 2.17.2 Method Loading ............................................................... 38 2.17.3 Resetting the MA235 ....................................................... 38
2.18 ISE Menu ......................................................................... 39
2.18.1 Electrode ID Selection ..................................................... 39 2.18.2 Incremental Technique Selection .................................... 39 2.18.3 Known Values for Incremental Techniques..................... 40 2.18.4 Sample Volumes for Incremental Techniques ................ 41
2.19 Chart Recorder ................................................................ 42
2.20 Interfacing via the RS232 Output .................................... 43
2.21 Using an Electrode Selector Box .................................... 46
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Contents (cont)
3 Support Information
3.1 Basic Theory .................................................................... 47
3.2 Operating Hints ................................................................ 48
3.3 Maintenance .................................................................... 50 3.3.1 MA235 Maintenance........................................................ 50 3.3.2 Electrode Maintenance .................................................... 50
3.4 Problem Solving .............................................................. 51
3.5 Specifications .................................................................. 54
Consumables and Accessories ...................................................... 56
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1.1 Installation
1. Unpack the meter, power supply, electrode, electrode arm,
buffer sachets, Guide Book and calibration certificate. Store
the calibration certificate in a safe place.
2. Check the power supply unit is the correct voltage for your
local supply. If it is not, contact your distributor.
3. Attach the electrode arm to the left or righthand side of the
meter:
a. Turn the meter upside down and seat the dome of the
electrode of the electrode arm base into the left or
righthand meter recess.
b. Insert and tighten the fixing screw.
c. Turn the meter and base the right way up and locate the
electrode arm onto the base fixing post. Press down to
snap into place.
1
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1.2 Input and Output Connections
1. Disconnect the shorting clips from the pH sockets and retainby clipping over the socket. If you are using two sensing
electrodes connect them to Channel A and B. If you are using
one electrode, connect it to Channel A.
2. Connect the reference electrode(s), if using, to the Refsocket(s).
3. If you are using an ATC probe connect it to theATC
socket.
If you are using a PT1000 probe connect it to the PT sockets.
4. Connect the power supply unit to the DC socket.
5. When the MA235 is powered up it carries out a display self test.
1power supplyunit socket
reference electrode sockets,Channel A & B
ATC (automatic temperaturecompensation) probe socket
combination or pH electrodesockets, Channel A & B
PT1000 (automatictemperature compensation)probe sockets
data output socket,see Section 2.20for interfacing details
recorder outputsocket, seeSection 2.19for details
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1.3 Controls
Selects pH, mV, relative mV, concentration, knownaddition or sample addition mode.
Accesses software menu from current mode. Exitssoftwaremenu one step at a time.
Selects automatic endpoint, timed endpoint or manualendpoint facility.
Turns the display off, and places the meter in standbymode. Wakes the meter up.
Starts a calibration sequence in pH, concentration andrelative mV modes. Starts sequence in known additionand sample addition modes.
Starts sample measurement in all modes. Press againto manually endpoint. Starts and stops timed datalogging. Returns to measurement from softwaremenu.
Enters sample ID mode.
Selects options in software menu, and enters data orselection.
Used to move around software menu.
Data entry keys, to set calibration buffers, date/time,high/low limits etc. Can also be used to move aroundsoftware menu quickly.
1
7 8 9
4 5 6
1 2 3
0 . -
>> >> > > > > > >
> > > > >> > > > >
Enter
ID
A
Prog
Mode
Read
OnOff
Cal
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2.1 pH Measurements
We recommend regular calibration before sample measurement
(see Section 2.1.1).
To measure the pH of a sample:
Place electrode in sample and press or start the
measurement.
The display shows the pH of the sample. If you are using a
temperature probe the sample temperature is shown, or you can
enter the temperature manually (see Section 2.13.2).
If you are using auto endpoint or timed endpoint the display
freezes automatically (see Section 2.7). To manually endpoint
and freeze the display press
To start a new measurement press
2.1.1 Calibrating a pH Electrode
NOTES If you are using a temperature probe the buffertemperature is shown, or you can enter the temperature
of the buffer manually (see Section 2.13.2).
If you are using auto endpoint or timed endpoint the
display freezes automatically (see Section 2.7). To
manually endpoint and freeze the display press
To calibrate an electrode:
Press If you are using both measurement channels
(A and B), select the one you want to calibrate
using and thenpress>
>
CalpH
Read
Enter
ReadpH
Read
Read
Read
Cal
2
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2.1.1 Calibrating a pH Electrode (cont)
The calibration buffers are shown on the display.
If you want to use other buffers, you will need to enter the values
(see Section 2.10.1).
1 point calibration
Place the electrode in the first buffer. At the measurement
endpoint a tick (4 ) appears on the display.
If you are using a standard buffer the display updates to the
temperature corrected value (see Section 3.5).
The electrode offset is displayed.
To return to sample measurement press
2 point calibration
To continue with a 2 point calibration:
Place the electrode in the second buffer and press
When the display freezes the electrode slope value will bedisplayed.
To return to sample measurement press
3, 4 and 5 point calibration
Repeat procedure using the third, fourth and fifth calibration
buffer.
NOTE The buffers can be selected for calibration in any order.
Use and to select the buffer you want to use
for the calibration and press
2
Read
Cal
Read
Cal
> >
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2
2.2 mV Measurements
To measure the absolute mV of a sample:
Place electrode in sample and press to start the measurement.
The display shows the absolute mV of the sample.
If you are using auto endpoint or timed endpoint the display freezes
automatically (see Section 2.7). To manually endpoint and freeze the
display press
To start a new measurement press
2.2.1 Relative mV Measurements
Place electrode in the reference sample and press
The display shows the mV of the reference sample.
If you are using auto endpoint or timed endpoint the display
freezes automatically (see Section 2.7). To manually endpoint and
freeze the display press
The display updates to 0.0, or an entered value (see Section 2.10.3).
To measure the relative mV of a sample:
Place electrode in sample and press to start the measurement.
The display shows the relative mV of the sample. If you are using
auto endpoint or timed endpoint the display freezes automatically
(see Section 2.7). To manually endpoint and freeze the display
press
If you entered a mV offset (see Section 2.10.3) the sample result
will be the difference between the measured and the set value.
To start a new measurement press
Read
Read
Read
Cal
Read
CalRel mV Mode Read
Read
Read
mV ReadMode
Read
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22.3.1 Calibrating an Ion Selective Electrode NOTES If you are using a temperature probe the temperature of
the standard is shown, or you can enter the temperature
of the standard manually (see Section 2.13.2).
If you are using auto endpoint or timed endpoint the
display freezes automatically (see Section 2.7). To
manually endpoint and freeze the display press
To calibrate an electrode:
Press If you are using both measurement channels
(A and B), select the one you want to calibrate
using and thenpress
2.3 Concentration Measurements
We recommend regular calibration before sample measurement(see Section 2.3.1).
To measure the concentration of a sample:
Place electrode in sample and press to start the
measurement.
The display shows the concentration of the sample (you can
change the units of measurement - see Section 2.11.2). If you areusing a temperature probe the sample temperature is shown or
you can enter the temperature manually (see Section 2.13.2).
If you are using auto endpoint or timed endpoint the display
freezes automatically (see Section 2.7). To manually endpoint
and freeze the display press
To start a new measurement press
concentration
Cal
CalMode
Read
Read
Read
>>
Enter
concentration Mode Read
Read
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2
2.3.1 Calibrating an Ion Selective Electrode (cont)
Five calibration standards are shown on the display. If you want
to use other standards, you will need to enter the values (see
Section 2.10.1).
1 point calibration
Place the electrode in the first standard. At the measurement
endpoint a tick (4 ) appears.
The electrode offset is displayed.
To return to sample measurement press
2 point calibration
To continue with a 2 point calibration:
Place the electrode in the second standard and press
When the display freezes the electrode slope value will be
displayed.
To return to sample measurement press
3, 4 and 5 point calibration
Repeat the procedure using the third, fourth and fifth calibration
standard.
NOTES The standard set for the first calibration standard is theisopotential point, calibrate in this standard first.
The five standards can be selected for calibration in anyorder.
Use and to select the standard you want
to use for the calibration and
press
Read
Read
Cal
> >
Cal
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2.4 Known Addition/Subtraction Measurements
Enter electrode type and electrode slope, volumes and standardconcentration before measurement (see Section 2.18).
To measure a sample by known addition/subtraction:
Place electrode in sample and press to start the
measurement.
The display shows the first part of the measurement (you can
change the units of measurement - see Section 2.11.2). If you areusing a temperature probe the sample temperature is shown or
you can enter the temperature manually (see Section 2.13.2).
If you are using auto endpoint or timed endpoint the display
freezes automatically (see Section 2.7). To manually endpoint
and freeze the display press
Add the standard to the sample and press
The sample result is shown. If you are using auto endpoint or
timed endpoint the display freezes automatically (see Section 2.7).
To manually endpoint and freeze the display press
NOTE known values (Section 2.18.3) - enter the volume andconcentration of the standard you are using, and the
slope of the electrode.
sample volumes (Section 2.18.4) - enter the volume of your sample as sample volume 1.
Read
Read
Cal
Cal Readk. add Mode
2Read
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2
2.5 Sample Addition/Subtraction Measurements
Enter electrode type and electrode slope, volumes and standardconcentration before measurement (see Section 2.18).
To measure a sample by sample addition/subtraction:
Place electrode in standard and press to start the
measurement.
The display shows the first part of the measurement (you can
change the units of measurement - see Section 2.11.2). If you
are using a temperature probe the temperature of the standardis shown or you can enter the temperature manually (see
Section 2.13.2).
If you are using auto endpoint or timed endpoint the display
freezes automatically (see Section 2.7). To manually endpoint
and freeze the display press
Add the sample to the standard and press
The sample result is shown. If you are using auto endpoint or
timed endpoint the display freezes automatically (see Section 2.7).
To manually endpoint and freeze the display press
You can enter volumes for 4 samples (see Section 2.18.4), so it is
possible to measure 4 samples using the same standard. You can
measure more than 4 samples (the MA235 assumes the samplevolume is that entered for sample volume 4) but for maximum
accuracy we recommend that you only measure 4 samples for
each standard.
To start a new measurement add the next sample to the
standard (and previous sample) and press
The MA235 uses the known values, plus the calculated samplevalue to calculate a new ‘standard value’ and therefore the new
sample measurement.
Cal
Cal Reads. add Mode
Read
Read
Read
Read
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2
2.5 Sample Addition/Subtraction (cont)
NOTE known values (Section 2.18.3) - enter the volume andconcentration of the standard you are using, and the
slope of the electrode.
sample volumes (Section 2.18.4) - enter the volume of your samples (up to 4).
2.6 Temperature Measurements
To measure the temperature of samples and calibration buffers
you must have a temperature probe connected (see Section 1.2).
Select which temperature mode you want to use for each channel
(see Section 2.13.1). If you are using a temperature probe place
the probe in the sample with the electrode when you calibrate
and measure in any mode. The temperature is displayed with the
reading, and the display shows ATC or PT1000.
If you do not have a temperature probe connected or if you
selected manual in temp mode, the display shows MTC. The
temperature displayed will either be the default value of 25°C, ora temperature entered manually, see Section 2.13.2.
2.7 Manual and Auto Endpoint, and Endpoint Time
The auto read control can be used in all modes toselect the endpoint method - manual, automatic or timed.
The automatic endpoint facility checks each measurement to see
if the electrode output is stabilizing, and when the stability
requirements have been met automatically endpoints the
reading. For solutions with long equilibration times (e.g. low
ionic strength samples) it is better to use manual or timed
endpoint.
The endpoint time facility freezes the display after a presetamount of time (see Section 2.13.3). The endpoint time facility is
turned off by setting the endpoint time to 00:00:00.
A
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2.8 Sample ID
The sample number counter increments 1 every time a sample
measurement is endpointed.
To change or reset the sample ID number press
Enter your required sample number using the keypad (enter 0 if
you want to reset the number) and press again.
NOTE If you press while measuring, the sample numberis assigned to that sample.
If you press when the measurement hasendpointed, the number will be
assigned to the next sample.
A
T
M
2.7 Auto Endpoint and Endpoint Time (cont)
Auto endpoint and endpoint time should not be used when using
timed interval data logging.
To use auto or timed endpoint:
press the auto endpoint indicator appears
Press again to select timed endpoint
During calibration or sample measurement the
decimal place flashes until a stable endpoint is
reached, or until the endpoint time has elapsed,
then the display freezes.
To cancel timed endpoint enter 0 as the endpoint time.
NOTES If 0 has been entered as the endpoint time, the manualendpoint indicator appears
The method of endpointing can be saved as part of a
method, see Section 2.17.1.
2 IDID
ID
ID
ID
A
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1 2 3 4 T h e M
A 2 3 5 u s e s a m e n u s y s t e m
f o r t h e s e t u p f u n
c t i o n s . T h e r e a r e n i n e
m e n u s , t h e s e a r e : c a l i b
r a t i o n ,
d i s p l a
y , s y s t e m 1 , s y s t e m 2 ,
l i m i t s ,
d a t a l o g ,
G L P , m e t h o d ,
I S E . T h i s c h a r t s
h o w s t h e n i n e m e n u s .
P r o g
1
2
3
4
5
6
7
8
9
c a l i
b r a t i o n
d i s p l a y
s y s t e m
1
s y s t e m
2
l i m i t s
d a t a l o g
G L P
m e t h o d
I S E
c a l p o i n t s
c h a n n e l
t i m
e / d a t e
t e m p m o d e
a l a r m
o n / o f f
o n / o f f
s a v e
e l e c t r o d
e I D
l a s t
c a l
c o n c u n i t s
l a n
g u a g e
s e t t e m p
s e t l i m i t s
t i m e r
c a l a l a r m
l o a d
i n c r e m e
n t a l
t e c h
m V
o f f s e t
p H
r e s o l u t i o n
b a u d
e n d p o i n t t i m e
t e m p
r e c a l l d a t a
I D
n o .
r e s e t
k n o w n v
a l u e s
i s o
b e e p e r
s e l f t e s t
s l o p e l i m i t s
c l e a r d a t a
s a m p l e
v o l u m e s
>
>
>
> E n t e r
U s e t h e a r r o
w k e y s t o m o v e a r o u n d t h e m e n u s .
T h e n u m e r i c
k e y p a d c a n b e u s e d a s q u i c k a c c e s s k e y s . F o
r e x a m p l e , t o c h a n g e t h e d i s p l a y
r e s o l u t i o n t o
X . X X p r e s s
t h e n
( t o a c c e s s m e n u
2 ) ,
( t o a c c e s s i t e m
3 ) ,
( t o s e l e
c t o p t i o n 2 ) .
T h i s i s u s e f u
l w h e n o p e r a t i n g t h e M
A 2 3 5 r e m o t e l y f r o m
a P C , s e e S e c t i o n 2 . 2 0 .
2
2
3
P r o g
2.9 Program Menu
2
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2.9 Program Menu (cont)
To access the menus:
press the display shows three menu titles at a time (if you
are using both measurement channels (A and B), youhave to select which channel you want to set up).
Press and to move round the menus.You can move
either way, and the menu wraps round
at each end.
Each time you press an arrow key
the next menu title appears, e.g. press
To access your chosen item press or
To choose from options displayed use and then press
Before you can enter or change a value the value must be flashing,
for example: cal 1 = 7.000
Press Change the flashing value using the keypad, then
press again.
Press to return directly to measurement.
< display system 1 system 2 >
channel
conc units Use to move down through the items.
pH resolution2
>>
>
Prog
< calibration display system 1 >
>
< display system 1 system 2 >
Enter
Enter
Enter
Enter
Enter
Enter
Enter
> >
>
Read
To access the menu items, press or when your
required menu is highlighted,
e.g. to access the display menu items press
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2
calibration
cal points
last cal
mV offset
iso
>>
>
Enter
Enter
Enter
Enter
>>
2.10 Calibration Programming
This menu allows you to set 5
calibration points for pH or
concentration; recall data for thelast 10 calibrations, set an offset
value for relative mV mode and set
the isopotential point for pH.
Default refers to the factory
setting which the MA235 uses if no
information is entered.
2.10.1 Calibration point setting
Press or when cal points is highlighted.
If you enter cal points from pH mode, the cal points for pHcalibration are set up. If you enter from concentration mode, the
concentration calibration points are set up, and the standard set
as the first calibration point is the isopotential point.
Use and to select the calibration pointyou want to change and press
The display flashes showing that the value can be changed.
Enter the required value using the keypad and press
# appears if you set a pH calibration value to a standard buffer,
(the value must be the pH value at 25°
C for the standard buffer).The MA235 stores temperature corrected values for the standard
buffers (see Section 3.5).
The next cal point is highlighted. If you want to change this next
point, press and continue as before.
Use and to select another calibration point to change,
OR
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2.10.1 Calibration point setting (cont)
press or to leave cal points without any furtherchanges.
Press to return directly to measurement.
NOTE The concentration range of the MA235 is 1.00E –9 to9.99E+9. Enter values in the normal way (for example,
100.0). If you enter a value within the range 0.0001 to
19999 this is how it will be displayed. If you enter avalue outside this range (for example 20500) it will be
converted to exponential format on the display (2.05E+4).
2.10.2 Last calibration recall
Press or when last cal is highlighted.
If you recall the data to the external printer it will print all the
calibration data logged (up to 10 calibrations).
If you recall the data to the display it is shown 4 calibrations at a
time.
Use and to scroll through the data; press to see
further information.
NOTES The MA235 can store data for the last 10 calibrations.
So, if for example 15 calibrations have been carried out,the MA235 stores the data for calibrations 6 to 15.
Calibration data cannot be cleared.
Press to leave last cal.
Press return directly to measurement.
2.10 Calibration Menu (cont)
Prog >
Read
Enter >
>
> > >
Read