quartz accelerometer ai-q-2010 ai-q-2020 ai-q-2030 user manual

AI-Q-20X0 Accelerometers User Manual IN-IR-MPD-72-256

Rev 1.0 22/09/2015

of 31 INNALABS PROPRIETARY INFORMATION

www.innalabs.com

Quartz Accelerometer

AI-Q-2010

AI-Q-2020

AI-Q-2030

USER MANUAL

Revision 1.0


Rev 1.0 22/09/2015


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PROPRIETARY NOTE

The information contained within this user manual (the “Documentation”) is proprietary to InnaLabs, and is intended solely for the use of InnaLabs customers, in the design or development of systems whose purpose is to operate using InnaLabs inertial sensors.

You may not reproduce, distribute, republish, download, display, post, or transmit this Documentation in any form or by any means including, but not limited to, electronic, mechanical, photocopying, recording, or otherwise, without the prior written consent of InnaLabs.

InnaLabs disclaims any liability arising out of use of this Documentation.

This Documentation is disclosed as seen with no warranties other than that defined in Appendix A.

© 2015 InnaLabs Ltd. All rights reserved.

INNALABS is a trademark of InnaLabs Ltd.


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This user manual supports the following INNALABS accelerometer part numbers:

AI-Q-2010

AI-Q-2020

AI-Q-2030

Quartz Pendulous Accelerometers

Technical and performance specifications, interface data and mounting guidelines are included.

Throughout this document, AI-Q-20X0 refers collectively to the 3 different part numbers AI-Q-2010, AI-Q-2020, and AI-Q-2030.


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TABLE OF CONTENTS

1. INTRODUCTION ........................................................................................................................ 6

1.1 Reference documents ........................................................................................................................... 6

1.2 Abbreviations ....................................................................................................................................... 6

1.3 Product description .............................................................................................................................. 6

1.4 Product Performance ........................................................................................................................... 7

1.5 Technology description ........................................................................................................................ 8

2. INTERFACES ............................................................................................................................. 10

2.1 Interface Control Drawing .................................................................................................................. 10

2.2 Electrical Interface and Wiring ........................................................................................................... 10

2.3 Mass ................................................................................................................................................... 14

2.4 Mounting ........................................................................................................................................... 15

2.5 Preliminary Testing ............................................................................................................................ 15

2.6 Electrical characteristics ..................................................................................................................... 17

3. FUNCTIONAL CHARACTERISTICS ..................................................................................... 18

3.1 General comment ............................................................................................................................... 18

3.2 Handling Requirements ...................................................................................................................... 18

3.3 Error model ........................................................................................................................................ 19

3.4 Start-up time ...................................................................................................................................... 19

3.5 Warm-up time .................................................................................................................................... 20

3.6 Input Acceleration and input Acceleration Limits ............................................................................... 20

3.7 Scale factor ......................................................................................................................................... 20

3.8 Bias .................................................................................................................................................... 21

3.9 Frequency response and bandwidth ................................................................................................... 22

3.10 Vibration Sensitivity ........................................................................................................................... 23


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3.11 Misalignment ..................................................................................................................................... 23

4. ENVIRONMENTAL CONDITIONS ........................................................................................ 24

4.1 Operating temperature ...................................................................................................................... 24

4.2 Non-Operating temperature .............................................................................................................. 24

4.3 Humidity ............................................................................................................................................ 24

4.4 Mechanical environment .................................................................................................................... 24

4.5 EMI - EMC ........................................................................................................................................... 26

5. PRODUCT MARKING .............................................................................................................. 26

6. PACKAGING AND TRANSPORT........................................................................................... 27

7. ACCEPTANCE TEST ................................................................................................................ 27

8. ACCEPTANCE TEST CERTIFICATE ..................................................................................... 29

9. TECHNICAL SUPPORT ........................................................................................................... 29

APPENDIX A – LIMITED WARRANTY ON HARDWARE ...................................................... 30


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1. INTRODUCTION

1.1 REFE RE NCE D OCU MENTS

[RD1] IEEE Std 1293-1998 R2008, IEEE Standard Specification Format Guide and Test

Procedure for Linear, Single-Axis, Nongyroscopic Accelerometers

[RD2] IN-IR-DWG-0447-02, AI-Q-20X0 Accelerometer Interface Control Document,

revision 2, 27/04/2015

1.2 ABBREV IA TIONS

°C Degrees Celsius ATC Acceptance Test Certificate dB Decibels EMC/EMI Electromagnetic Compatibility, Electromagnetic Interference g Acceleration due to gravity GND Ground Hz Hertz ICD Interface Control Document K Kelvin mA Milliamps mrad Milliradians MTBF Mean Time Between Failures mV Millivolts mW Milliwatts N/A Not Applicable Ppm Parts Per Million PSD Power Spectral Density rad Radians RMS Root Mean Square s Second T Temperature V Volts VDC Volts Direct Current W Watts

1.3 PRODUCT DE SC RIPTION

The AI-Q-20X0 is a family of single axis, closed loop quartz pendulous accelerometers. These accelerometers offer navigation grade performance with exceptional repeatability and reliability, making it the ideal choice for demanding navigation systems. Each accelerometer is provided with thermal compensation models for bias, scale factor and misalignment (up to 4th order), and is focussed on fulfilling the operational requirements of inertial systems which require navigation grade performance, low output noise, large bandwidth, small size, low weight and high reliability.


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The accelerometer is ready for use within 100 milliseconds of power-on (typically 20 ms) and provides an analogue current output proportional to applied acceleration along the reference axes (up to ±60 g).

1.4 PRODUC T PE RFORMANC E

Parameters Units AI-Q-2010 AI-Q-2020 AI-Q-2030

Input Range g ±60 ±60 ±60

Bias mg <4 <4 <4

One-year Composite Repeatability (3) μg <550 <220 <160

Temperature Sensitivity µg/°C <30 <30 <30

Scale Factor mA/g 1.2 to 1.46 1.2 to 1.46 1.2 to 1.46

One-year Composite Repeatability (3) ppm <600 <500 <310

Temperature Sensitivity ppm/°C <180 <180 <180

Axis Misalignment µrad <2000 <2000 <2000

One-year Composite Repeatability (3) µrad <100 <100 <100

Vibration Rectification μg/g2RMS

<40 (50-500 Hz) <150 (500-2000 Hz)

<40 (50-500 Hz) <60 (500-2000 Hz)

<20 (50-500 Hz) <60 (500-2000 Hz)

Intrinsic Noise μgRMS <7 (0-10 Hz)

<70 (10-500 Hz) <1500 (500-10 kHz)

<7 (0-10 Hz) <70 (10-500 Hz)

<1500 (500-10000 Hz)

<7 (0-10 Hz) <70 (10-500 Hz)

<1500 (500-10000 Hz)

Operating Temperature °C -55 to +95 -55 to +95 -55 to +95

Shock g 250 250 250

Vibration Peak Sine g, Hz 15g @ 20 to 2000 Hz 15g @ 20 to 2000 Hz 15g @ 20 to 2000 Hz

Resolution/Threshold μg <1 <1 <1

Bandwidth Hz >300 >300 >300

Temperature Model Yes Yes Yes

Quiescent Current per Supply mA <16 <16 <16

Quiescent Power @ ±15VDC mW <480 <480 <480

Electrical interface

Temp Sensor Temp Sensor Temp Sensor

Voltage Self-Test Voltage Self Test Voltage Self Test

Current Self-Test Current Self Test Current Self Test

Power/Signal Ground Power/Signal Ground Power/Signal Ground

-10 VDC Output -10 VDC Output -10 VDC Output

+10 VDC Output +10 VDC Output +10 VDC Output

Input Voltage VDC ±13 to ±28 ±13 to ±28 ±13 to ±28

Weight g 71 ±4 71 ±4 71 ±4

Diameter below mounting surface mm 25.45 Max Ø 25.45 Max Ø 25.45 Max

Height – bottom to mounting surface mm 14.85 Max 14.85 Max 14.85 Max

Case Material 300 Series Stainless

Steel 300 Series Stainless

Steel 300 Series Stainless

Steel


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1.5 TECHNOLOGY DE SC RIPTIO N

The core of the proof (or seismic) mass of InnaLabs® pendulous accelerometers is a high purity fused quartz disc structure connected to a rigid outer frame by two thin hinges (Figure 1). The overall structure is monolithic and a deposited gold film is used to form an electrode pattern onto the surface of the pendulum as required for capacitive detection and for connection to the torque conducting leads

Figure 1 – Pendulum

Figure 2 – Accelerometer

Each accelerometer (Figure 2) includes a central ‘cell’, which contains the pendulum and electrostatic and electromagnetic circuit components used as parts of the closed loop control system.

When acceleration is applied perpendicularly to the proof mass, the servo loop circuit derives an error signal from the capacitive detection and delivers a current into two coils attached symmetrically to each side of the proof mass. Laplace forces are then applied to the winding and therefore the proof mass will be maintained in a capture or null mode with its centre in a null position, over a broad frequency band of input accelerations (i.e. >2 kHz typical). As the current through the coils is proportional to the applied acceleration, the same current flowing through an external load resistor will then generate an output voltage proportional to acceleration.

Figure 3 shows a simplified diagram of the closed loop system.


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N

S

Pendulum

N

S

Capacitive Plate(Lower Case)

Current Amplifier

&PID Control

Servo Amplifier

-

+

Feedback Compensation

Signal OutPin 1

Current TorquePin 2

Self TestPin 7

Torque Motor Coils

Capacitive Plate(Upper Case)

Magnet(Upper Case)

Magnet(Lower Case)

Torque Motor Coil(Upper Case)

Torque Motor Coil(Lower Case)

DetectorLower Case

Temperature OutputPin 6

Power Supply

Negative Power SupplyPin 3

Positive Power SupplyPin 4

GroundPin 8

-9VPin 9

+9VPin 10

GND

VIN-

VIN+

– VREF+ VREF

Upper Case

Note: The mechanical (chassis) ground is isolated from the electrical ground (pin 8)

Figure 3 – System Block Diagram

The current required in the torque motor coils to re-centre the pendulum is directly proportional to the applied acceleration. This current is output on the Signal Out pin as the acceleration signal. Typically, a precision resistor is used externally to the accelerometer to convert the current output to a voltage.


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The definition of the accelerometer axes, as described in annex 3 of [RD1], are shown in Figure 4.

Input Axis (IA)

Hinge Axis (OA)

Pendulum Axis (PA)

Figure 4 – AI-Q-20X0 Axes

The axes are:

Input Axis (IA) – The sensitive axis of the accelerometer

Pendulous Axis (PA) – The axis normal to the plane of the pendulum

Output (Hinge) Axis (OA) – The axis parallel to the line through the hinge of the pendulum

The positive direction of OA is defined by the vector operation:

𝐼𝐴⃗⃗⃗⃗ × PA⃗⃗⃗⃗ ⃗ = OA⃗⃗⃗⃗ ⃗

Note: For more information about the technology or physical principles see [RD1] , Annex C, pp. 110-117:

2. INTERFACES

2.1 INTE RFACE CONTROL DRAWING

The reference document [RD2] provides all necessary information about the AI-Q-20X0 mechanical interfaces.

2.2 ELEC TRIC AL INTERFA CE AND W IRING

The AI-Q-20X0 has ten connection pins, as shown in Figure 5, below.


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Figure 5 – AI-Q-20X0 Pins

The assignment of pins on the AI-Q-20X0 is shown in the following table:

Pin Function Type Characteristics

1 Signal Out Analogue Acceleration output, current signal, section 2.2.1

2 Current Torque Analogue Current input test pin, section 2.2.5

3 Negative Power Supply Power -13 V to -28 V, section 2.2.4

4 Positive Power Supply Power +13 V to +28 V, section 2.2.4

5 Not Connected N/A Do not connect to this pin.

6 Temperature Sensor Output Analogue Temperature output, current signal, section 2.2.3

7 Voltage Self-Test Analogue Voltage input test pin, section 2.2.5

8 Signal & Power Return Ground Ground reference for power supplies and signals

9 -10 V DC Analogue Voltage output, section 2.2.5

10 +10 V DC Analogue Voltage output, section 2.2.5

2.2.1 Electrical Connection

The diagram in Figure 6 shows the connections to the accelerometer for normal operation.


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Power Supply

+VIN -VIN GND

RMEAS

RTEMP

UTEMP

UMEAS

12

3

4

5

6

78

Figure 6 – AI-Q-20X0 Measurement Connections

2.2.2 Acceleration Measurement

The AI-Q-20X0 accelerometer produces an output current proportional to the acceleration applied along the sensitive axis of the accelerometer.

The output of the accelerometer is typically connected to a load resistor, RMEAS, which provides a voltage output, UMEAS. The nominal output is:

𝐴𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 (𝑔) =( 𝑈𝑀𝐸𝐴𝑆(𝑉)

𝑅𝑀𝐸𝐴𝑆(𝛺)× 103)

𝑆𝑐𝑎𝑙𝑒 𝐹𝑎𝑐𝑡𝑜𝑟(𝑚𝐴𝑔⁄ )

− 𝐵𝑖𝑎𝑠(𝑔)

2.2.3 Temperature Measurement

The AI-Q-20X0 internal temperature sensor produces an output current proportional to absolute temperature. The device acts as a high impedance, constant current regulator passing 1 µA/°C. The temperature sensor is calibrated to output 303.2 µA at 30 °C (303.2 K).

Parameters of the internal temperature sensor are shown in the table below.

Parameters Units Values

Typical Maximum

Nominal Current Output at 30 °C µA 303.2

Nominal Temperature Coefficient µA/°C 1

Calibration Error @ 30 ° °C ±5.0

Nonlinearity#1 °C ±1.5

Repeatability °C ±0.1


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Parameters Units Values

Long-Term Drift °C ±0.1

Current Noise pA/√Hz 40

Effective Shunt Capacitance pF 100

Electrical Turn-On Time µs 20

Note #1: Nonlinearity is defined as the deviation of current over temperature from a best-fit straight line.

The output of the temperature sensor is typically connected to a load resistor RTEMP, which provides a voltage output, UTEMP. The nominal output at a given temperature is:

𝑇𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 (°𝐶) = ( 𝑈𝑇𝐸𝑀𝑃(𝑉)

𝑅𝑇𝐸𝑀𝑃(𝛺)× 106) − 273.2

2.2.4 Power Supplies

The AI-Q-20X0 requires a bipolar power supply in the range ±13 V to ±28 V. It is not necessary for the two supplies to be of equal magnitude. The quiescent current consumption will increase at higher input voltages.

The AI-Q-20X0 has a ripple rejection characteristic as shown in Figure 7 (for an RMEAS value of 1 kΩ). The ripple rejection is presented in dB(mA/V), as the acceleration sensitivity depends on the scale factor.

Figure 7 – AI-Q-20X0 Ripple Rejection Characteristics

2.2.5 Test Functionality

The AI-Q-20X0 has three options for test functionality: the current torque connection (pin 2), the voltage self-test connection (pin 7) and the voltage output pins (pins 9 and 10).

0

10

20

30

40

50

60

70

80

90

100

1 10 100 1000 10000 100000

PSR

R [

dB

(ma/

V)]

Frequency [Hz]

Positive Rail Negative Rail


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2.2.5.1 Current Torque

The current torque pin (2) is a current input pin. Current on this pin is injected into the output of the servo amplifier, as shown in Figure 3. The servo loop acts to null the injected current, increasing current draw on the appropriate power pin (a positive input current increases current draw on the negative supply and vice versa):

Positive Current on Pin 2 = Negative Current on Pin 3

Negative Current on Pin 2 = Positive Current on Pin 4

This functionality can be used to verify that the electronics in the accelerometer can deliver the current required under high g conditions (static and/or dynamic). Based on the scale factor of the accelerometer:

𝑆𝑖𝑚𝑢𝑙𝑎𝑡𝑒𝑑 𝑎𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 (𝑔) = 𝐴𝑝𝑝𝑙𝑖𝑒𝑑 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 (𝑚𝐴)

𝑆𝑐𝑎𝑙𝑒 𝐹𝑎𝑐𝑡𝑜𝑟 (𝑚𝐴𝑔⁄ )

In normal operation, this pin should be left unconnected.

2.2.5.2 Voltage Self-Test

The voltage self-test pin (7) is a voltage input pin. A voltage applied to this pin injects a signal into the integrator of the control loop electronics, as shown in Figure 3. As the integrator input is offset (assuming a DC input), the servo loop compensates the input, offsetting the position of the pendulum, and is visible as a transient on the accelerometer output. A step input to this test pin can be used to measure the accelerometer bandwidth from the transient response.

In normal operation, this pin should be left unconnected.

2.2.5.3 Voltage Output Pins

Pins 9 and 10 of the accelerometer are used to check the correct operation of the AI-Q-20X0 internal electronics. In normal operation, the output of these pins can be measured:

Pin 9 Output = –10 VDC

Pin 10 Output = +10 VDC

In normal operation, these pins should be left unconnected, as loading these pins can affect the operation of the accelerometer.

2.3 MA SS

The mass of the AI-Q-20X0 accelerometers is 71 g ±4 g.


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2.4 MOUNTING

The external mounting holes for the AI-Q-20X0 are shown in Figure 8 (see [RD2] for full details). The mounting holes are designed for metric M3 screws with a tightening torque of 20 – 40 cNm.

Figure 8 – AI-Q-20X0 Mounting Holes

N.B.: For optimum thermal misalignment performance, it is recommended the accelerometer be mounted to a 300 series stainless steel base

The recommended material for screws is stainless steel, in order to match the thermal expansion rate of the accelerometer housing.

During mounting, if a torque wrench is used, it is recommended to maintain it not triggered, in order to avoid propagating shocks into the accelerometer.

2.5 PRE LIMINA RY TE STING

Before connecting and mounting the AI-Q-20X0, a simple familiarisation test is suggested if this is the User’s first introduction to the product. This test will also verify proper unit operation and assist in troubleshooting.

2.5.1 Equipment needed to Test

±(13 – 28) VDC power supply limited to 20 mA

Load resistor (RMEAS), up to 10 kΩ

A voltmeter / oscilloscope

2.5.2 Test Procedure

Place the AI-Q-20X0 on a flat surface with the connector pins facing up.


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Connect the power supply according to §2.2 (positive supply to pin 4 and negative

supply to pin 3, ground to pin 8).

Connect the load resistor between the Signal Out (pin 1) and Signal Return (pin 8).

Connect the voltmeter / oscilloscope across pins 1 (Signal Out) and 8 (Signal/Power

Return) of the AI-Q-20X0 interface connector to test

Wires can be connected to the accelerometer using a test connector (InnaLabs can provide these connectors on request), or by soldering wires directly to the pins. If soldered connections are used, this should be done as per the state of the art, in such a way as to avoid short circuits between pins.

Figure 9 – Electrical Connection to AI-Q-20X0

2.5.2.1 ±1 g Tumble Test

Switch on the power supply

Observe the output of the accelerometer on the voltmeter / oscilloscope.

o The output should show the equivalent of +1 g, according to the following

equation (from Figure 6):

Acceleration = (UMEAS / RMEAS) / Scale Factor

Rotate the accelerometer through 180°, so that the connector pins are now facing

down.

o The output should now show the equivalent of -1 g.

Switch off the power supply.

Figure 10 and Figure 11 show the orientations for ±1 g measurements.


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Figure 10 – +1 g Orientation

Figure 11 – -1 g Orientation

2.6 ELEC TRIC AL CHA RACTE RI ST IC S

2.6.1 Load Resistor Selection

The external resistor used affects the maximum g-range measurable by the test system, due to voltage drop across both it and the internal coil resistance.

𝐴𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝑅𝑎𝑛𝑔𝑒 (@30 °𝐶) = 1000 × 𝑉𝐼𝑁

𝐾1(𝑅𝐿 + 𝑅𝑀𝐸𝐴𝑆)

Where:

VIN: Absolute Power Supply Voltage

K1: Scale Factor (from ATC)

RL: Coil Resistance (from ATC)

RMEAS: Measurement Resistance

For example:

VIN = ±13 V

K1 = 1.20 mA/g

RL = 170 Ω

RMEAS = 10 Ω

The acceleration range (at which point the accelerometer output saturates) using the parameters above is ±60.2 g. As the input voltage is increased, a larger voltage drop is available, enabling the same acceleration level to be measured with a larger measurement resistor (thus improving signal-to-noise ratio). Using the same formula with a 215 Ω measurement resistor, at ±28 V, the saturation range is ±60.6 g.

With a scale factor of 1.46 mA/V, a 147 Ω (or less) resistor is required at ±28 V in order to meet the full measurement range.

The absolute acceleration limit over temperature is dependent on the range of the parameters in the equation above.


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This can be re-written as:

𝐴𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝐿𝑖𝑚𝑖𝑡 = (1000 × 𝑉𝐼𝑁)𝑀𝐼𝑁

𝐾1𝑀𝐴𝑋 × (𝑅𝐿𝑀𝐴𝑋+ 𝑅𝑀𝐸𝐴𝑆𝑀𝐴𝑋

)

When selecting a load resistor, the resistance of any associated interconnecting cables must be taken into account as these add to the overall resistance. As such, the maximum cable length depends on the voltage drop that can be tolerated.

It is recommended the resistance (and by association the length) of the cable is kept to a minimum in order to minimise variations in the measured output due to resistance changes over temperature.

3. FUNCTIONAL CHARACTERISTICS

3.1 GENERAL C OMMENT

When not specified, the performance detailed below is available over the full operating conditions as described in section 4.

3.2 HAND LING REQU IREME NTS

Preventing ESD Damage

An unpackaged AI-Q-20X0 is to only be handled, stored or transported in an ESD

protected area [EPA]

When handling the accelerometer, the person is to be grounded via a wrist strap system

or a flooring/footwear system

Outside the EPA, the AI-Q-20X0 is to be enclosed in ESD protective packaging. An

unpackaged AI-Q-20X0 inside the EPA is to be stored or transported on grounded work

surfaces or shelving

When soldering to the pins the soldering iron tip should be grounded. Alternatively,

prior to connecting the accelerometer pins to the user system (including cable wires,

power supply, electronics, etc.), as a precaution, it is recommended that all pins be

shorted to the mechanical ground (accelerometer housing). Once the accelerometer is

connected to the user system, before power on, the short to ground should be released

Preventing Physical Damage

Handle the AI-Q-20X0 with care at all times

The unpowered shock limit of the AI-Q-20X0 is 250 g in any axis

Preventing Electrical Damage

Do not touch or make connections to the unit with the power on. Doing so may damage

the unit and/or cause injury to personnel


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Double-check all test equipment connections before applying power

Use battery-operated test equipment whenever possible

Make sure that all test equipment is isolated from ground

3.3 ERROR MODEL

3.3.1 General

When the pendulum is servo controlled in position, the current in the torque motor acts as a biased estimator of the specific force applied along the pendulum input axis.

The accelerometer model equation is defined as a series that mathematically relates the accelerometer output am to the components of applied acceleration along the reference axes. Each accelerometer input axis has two misalignments relative to the nominal IA, in the IA-PA and IA-OA planes.

The expression of the accelerometer model at the centre of mass of the pendulum is:

𝑎𝑚 =𝑖

𝐾1

𝑎𝑚 = 𝐾0 + 𝑎𝑆 + 𝐾2𝑎𝑆2 + 𝛿𝑃𝑎𝑂 + 𝛿𝑂𝑎𝑃 + 휀

Where:

𝑎𝑚 Indicated accelerometer output (g)

𝑎 = (𝑎𝑠, 𝑎𝑝, 𝑎𝑜) Components of the acceleration along the nominal I, P and O axes (g)

𝑖 Accelerometer output current (mA)

𝐾0 Bias (g)

𝐾1 Scale factor of the torque motor (mA/g)

𝐾2 Quadratic nonlinearity (g/g²)

𝛿𝑃, 𝛿𝑂 Direction cosine misalignment angle of the IA axis relative to the nominal in the IA-PA and IA-OA planes (rad)

휀 Un-modelled error (g)

𝑉𝑎𝑙(𝑔) 9.81792 m/s-2 at InnaLabs Dublin (IRELAND)

3.3.2 Thermal Modelling

The accelerometer performance over temperature is modelled for bias, scale factor and misalignment using polynomial functions (first to fourth order), generated using the least-squares method.

3.4 STA RT-UP T IME

The accelerometer output is within 5% of the input acceleration, at an input acceleration of ±1 g, within 100 ms of power on (20 ms typical).


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3.5 WARM-UP TIME

At ambient temperature (25 °C ± 5 °C), over the first 30 minutes of operation, the un-modelled parameters and the modelled parameters of the accelerometer drift as shown in the table below. After 30 minutes, the performance parameters are described by the following sections:

Warm-Up Drift

No Temp. Comp. With Temp. Comp.

Bias, K0 20 µg 5 µg

Scale Factor, K1 20 ppm 5 ppm

3.6 INPU T ACCE LE RA TION A ND INPU T AC CELE RA TION L IMITS

Once the applied in-axis acceleration comes back within the operational limits, the recovery time to get a functional output with full performance is less than 10 ms.

Measurable input acceleration limits along the sensitive axis (IA) of the AI-Q-20X0:

|𝛾| ≤ 60 𝑔 (= 𝛾𝑙𝑖𝑚)

The measurable acceleration limit is also affected by the selection of the load resistor, see section 2.6.1.

3.7 SCA LE FAC TOR

3.7.1 Nominal value

The scale factor nominal value is in the range:

K1 1.20 mA/g – 1.46 mA/g

3.7.2 Scale factor thermal sensitivity

At the beginning of life, the average change in the scale factor resulting from a change in steady state operating temperature is as follows:

dK1/dT ≤ 180 ppm/°C

3.7.3 Scale factor One Year Composite Repeatability

The scale factor one year composite repeatability parameter is the overall variation arising from a number of different errors, including hysteresis and ageing, and under some specific external conditions. The mission profile considered is based on two full-range temperature cycles per month.


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The scale factor one year composite repeatability takes the form (3 values):

AI-Q-2010 AI-Q-2020 AI-Q-2030

K1 One year composite repeatability ≤ 600 ppm ≤ 500 ppm ≤ 310 ppm

3.8 B IA S

3.8.1 Bias offset at 30 °C

After the warm-up phase, at 30°C:

|K0| ≤ 4 mg

3.8.2 Allan Variance

A typical Allan deviation plot is shown in Figure 12.

Figure 12 – Allan Variance

3.8.3 In-run bias stability

After the warm-up phase, at 30 °C:

In-run stability ≤ 0.1 µg rms at 20 s to 100 s

3.8.4 Velocity random walk

After the warm-up phase, at 30 °C:

VRW 14 µg.s/hr (typical)


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3.8.5 Quiescent noise

The spectral noise is defined in several bandwidths, as follows:

0-10 Hz <7 µgRMS

10-500 Hz <70 µgRMS

500-10,000 Hz <1500 µgRMS

The quiescent noise of the accelerometer output is also affected by power supply noise rejection, as per section 2.2.4.

3.8.6 Bias turn-on to turn-on repeatability

After the warm-up phase, at room temperature, the bias turn-on to turn-on repeatability is better than 10 µg, assuming a time off limited to 5 seconds.

3.8.7 Bias thermal sensitivity

At the beginning of life, the bias shift resulting from a change in steady state operating temperature is as follows:

dK0/dT ≤ 30 µ𝑔/°𝐶

3.8.8 Bias One Year Composite Repeatability

The bias one year composite repeatability parameter is the overall variation arising from a number of different errors, including hysteresis and ageing, and under some specific external conditions. The mission profile considered is based on two full-range temperature cycles per month.

The bias one year composite repeatability takes the form (3):

AI-Q-2010 AI-Q-2020 AI-Q-2030

K0 One year composite repeatability <550 µg <220 µg <160 µg

3.9 FRE QUENC Y RE SPONSE A N D BANDWID TH

The frequency response of the AI-Q-20X0 along the sensitive axis, IA fulfils:

𝐺𝑎𝑖𝑛 − 3 𝑑𝐵 𝑝𝑜𝑖𝑛𝑡 ≥ 300 𝐻𝑧

𝑃ℎ𝑎𝑠𝑒 − 90° 𝑝𝑜𝑖𝑛𝑡 ≥ 300 𝐻𝑧

Figure 13 and Figure 14 show typical gain and phase responses of the AI-Q-20X0.


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Figure 13 – AI-Q-20X0 Gain Response

Figure 14 – AI-Q-20X0 Phase Response

3.10 V IBRATION SENSIT IVITY

After the warm-up phase, at 30 °C, under random vibrations as per paragraph 4.4.2, the vibration rectification takes the form:

AI-Q-2010 AI-Q-2020 AI-Q-2030

50 – 500 Hz ≤ 40 µg/g²RMS ≤ 40 µg/g²RMS ≤ 20 µg/g²RMS

500 – 2000 Hz ≤ 150 µg/g²RMS ≤ 60 µg/g²RMS ≤ 60 µg/g²RMS

3.11 M I SA LIGNME NT

3.11.1 Misalignment at 30 °C

The misalignment absolute value at 30 °C (input axis, IA, relative to pendulous, PA, and output, OA, axes):

|δP|,|δO| ≤ 2 mrad

-35.00

-30.00

-25.00

-20.00

-15.00

-10.00

-5.00

0.00

5.00

10 100 1000 10000

Gai

n [

dB

]

Frequency [Hz]

-150.00

-100.00

-50.00

0.00

50.00

100.00

150.00

200.00

10 100 1000 10000

Ph

ase

[°]

Frequency [Hz]


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3.11.2 Misalignment Thermal Sensitivity

At the beginning of life, the average change in the misalignment resulting from a change in steady state operating temperature is as follows:

dδP/dT, dδO/dT ≤ 2 rad/°C typical

3.11.3 Misalignment One Year Composite Repeatability

The misalignment one year composite repeatability parameter is the overall variation arising from a number of different errors, including hysteresis and ageing, and under some specific external conditions. The mission profile considered is based on two full-range temperature cycles per month.

The misalignment one year composite repeatability takes the form (3):

One year composite repeatability <100 µrad

4. ENVIRONMENTAL CONDITIONS

4.1 OPERATING TEMPERATU RE

The operating temperature range is -55 °C to +95 °C.

Performance parameters for the accelerometers are measured at static temperatures using a thermal slope of ±3 °C/minute between each measurement point.

The maximum thermal slope which should be applied to the accelerometer is ± 5 °C/min.

4.2 NON-OPE RA TING TE M PE RA TU RE

The non-operating temperature range is -55 °C + 95 °C.

The maximum thermal slope which should be applied to the accelerometer is ± 10 °C/min.

4.3 HUMIDITY

The AI-Q-20X0 is hermetically sealed, enabling high tolerance to external humidity over the full operating temperature range, without any effect on performance.

4.4 MECH ANICA L ENVIRONMEN T

When rigidly fixed to an appropriate mount, the AI-Q-20X0 can be subjected to the following mechanical environments without damaging the unit.


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4.4.1 Half-sine shocks

Half-sine shocks as per the table below:

Direction Amplitude

[g peak] Duration

[ms]

𝑿, 𝒀, 𝒁 70 10

𝑿, 𝒀, 𝒁 110 8

𝑿, 𝒀, 𝒁 250 4

4.4.2 Random vibrations

Unpowered random vibration profile as per below table (X, Y, Z directions, 60 min per axis), equal to 6 gRMS:

Amplitude Frequency

0.0185 g2/Hz 5 Hz to 2 000 Hz

Powered random vibration profile as per below table (X, Y, Z directions, 3 min per axis), with 14 gRMS:

Amplitude Frequency

0.0985 g2/Hz 5 Hz to 2 000 Hz


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4.4.3 Sine vibrations

The AI-Q-20X0 performance is unaffected by exposure to the following unpowered sine vibrations shown in the table below and Figure 15.

Amplitude Frequency

1 gPEAK 5 Hz

5 gPEAK 10 Hz

5 gPEAK 35 Hz

35 gPEAK 55 Hz

35 gPEAK 120 Hz

10 gPEAK 200 Hz

10 gPEAK 400 Hz

8 gPEAK 400 Hz

8 gPEAK 1 000 Hz

5 gPEAK 1 000 Hz

5 gPEAK 2 000 Hz

Figure 15 – AI-Q-20X0 Sine Vibration Profile

4.4.4 Drop

Not applicable.

4.5 EMI - EMC

The AI-Q-20X0 is not ESD or EMC/EMI protected.

5. PRODUCT MARKING

The AI-Q-20X0 is engraved with the following information:

The InnaLabs logo

1

10

100

1 10 100 1000

g Le

vel (

g PEA

K)

Frequency (Hz)


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The part number

The accelerometer serial number

The accelerometer date code

The accelerometer serial number in 12 x 12 ECC200 data matrix format

An example of the part marking is shown in Figure 16.

Figure 16 – AI-Q-20X0 Product Marking

6. PACKAGING AND TRANSPORT

Before delivery, the AI-Q-20X0 is packaged into a specific box for shipment and storage in order to ensure receipt in good and proper operating order.

ESD protection is required during shipping.

7. ACCEPTANCE TEST

The following tests are carried out through the product Acceptance Test Procedure (ATP) on all accelerometers delivered:


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Parameter Paragraph Rate Units Limit

Scale Factor Nominal Value @ 30 °C 3.7.1 100 % mA/g 1.2 to 1.46

Scale factor Thermal Sensitivity 3.7.2 100 % ppm/°C ≤±180

Bias Nominal Value @ 30 °C 3.8.1 100 % mg ≤±4

Bias Thermal Sensitivity 3.8.7 100 % µg/°C ≤±30

Misalignment Nominal Value @ 30 °C 3.11 100 % µrad ≤±2,000

Misalignment Thermal Sensitivity 3.11 100 % µrad/°C ≤±3

Quiescent Noise at 100 Hz 3.8.5 100 % µARMS ≤10

Coil Resistance N/A 100 % Ω 155 to 185


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8. ACCEPTANCE TEST CERTIFICATE

With each accelerometer delivered, an acceptance test certificate (ATC) is provided containing the following information:

Parameter

Bias Nominal Value at 30 °C

Scale Factor Nominal Value at 30 °C

Misalignment Nominal Value at 30 °C

Bias Average Thermal Slope over Temperature

Scale Factor Average Thermal Slope over Temperature

Misalignment Average Thermal Slope over Temperature

Coil Resistance

Bias 1st, 2nd, 3rd and 4th Order Thermal Model

Scale Factor 1st, 2nd, 3rd and 4th Order Thermal Model

Misalignment 1st, 2nd, 3rd and 4th Order Thermal Model

9. TECHNICAL SUPPORT

For technical support please email your question or a description of your problem to [email protected]


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APPENDIX A – L IMITED WARRANTY ON HARDWARE

InnaLabs Limited (“InnaLabs”) warrants the product purchased from InnaLabs (“the product”) will be free from defect in material and workmanship for up to one (1) year following the date of delivery of the product to the Buyer.

InnaLabs warrants that the Product performance of will be within the performance criteria set out in the data sheets supplied with the product.

If the Buyer discovers a defect or non-compliance in performance in the Product covered in this limited warranty, InnaLabs will, at its option repair or replace the Product at no charge to the Buyer, or refund the purchase price paid for the product.

The Buyer must notify InnaLabs of the defect within 7 days of becoming aware of it and comply with InnaLabs instructions for returning the defective product. Reasonable shipping costs will be paid by InnaLabs.

Buyer must send to InnaLabs Test results demonstrating evidence of the non-conformance or defect.

This warranty will not be valid if the Buyer does not store the Products in accordance with InnaLabs User Manual.

This warranty does not apply if the Product has been damaged by accident, abuse, misuse, or misapplication or has been modified in any way without the prior permission of InnaLabs; if any InnaLabs serial number has been removed or defaced or if any factory-sealed part of the Product has been opened without authorisation.

Prior to returning any Product under this warranty you must contact InnaLabs Technical Support by phone (+ 353 1 809 6200) and obtain a RMA (Return Material Authorisation) number. Returned product should be shipped, where possible, in the original InnaLabs packaging supplied with the product. InnaLabs will not take responsibility for damage to product happening during the shipping process from the Buyer to InnaLabs.

THE EXPRESS WARRANTIES SET FORTH ABOVE ARE THEONLY WARRANTIES GIVEN BY INNALABS WITH RESPECT TO ANY PRODUCT FURNISHED HEREUNDER; INNALABS MAKES NO OTHER WARRANTIES EXPRESS, IMPLIED OR ARISING BY CUSTOM OR TRADE USAGE, AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR OF FITNESS FOR A PARTICULAR PURPOSE. SAID EXPRESS WARRANTIES SHALL NOT BE ENLARGED OR OTHERWISE AFFECTED BY TECHNICAL OR OTHER ADVICE OR SERVICE PROVIDED BY INNALABS IN CONNECTION WITH ANY PRODUCT.

InnaLabs liability in contract, tort or otherwise arising out of or in connection with any Product shall not exceed the price paid for the Product.

IN NO EVENT SHALL INNALABS BE LIABLE FOR SPECIAL, PUNITIVE, INCIDENTAL, TORTOR CONSEQUENTIAL DAMAGES OR LOST PROFITS OR GOODWILL (INCLUDING ANY DAMAGES RESULTING FROM LOSS OF USE, DELAY IN DELIVERY OR OTHERWISE) ARISING OUT OF OR IN CONNECTION WITH THE PERFORMANCE OR USE OR POSESSION OF ANY PRODUCT, OR ANY OTHER OBLIGATIONS RELATING TO THE PRODUCT, EVEN IF INNALABS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

If any implied warranty, including implied warranties of merchantability and fitness for a particular purpose, cannot be excluded under applicable law, then such implied warranty shall be limited in duration to one (1) year from the date of purchase of the Product.


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END OF DOCUMENT

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