Memsic AHRS500GA-203, AHRS500GA-200, AHRS500GA-201, AHRS500GA-202, AHRS500GA-204 Operator's Manual

Powerful Sensing Solutions for a Better Life

AHRS500GA Series

OPERATORS MANUAL

Document Part Number: 7430-0060-09 Rev A

MEMSIC, Inc., 1759 McCarthy Blvd, Milpitas, CA 95035

Tel: [phone], Fax: [phone]

email: [e-mail], website: www.memsic.com

AHRS500GA-[] Series Operator’s Manual

Revision Date Author Comments

-01_A 9/16/02 JR Initial Release

-02_A 12/02 DJ Added limitation section, changed startup

-03_A 11/03 DJ Changed the alignment process

-04_A 08/04 GB Updated manual to be specific to model

-05_A 12/04 DIP Added -224 and -220 models to support

-06_A 2/05 GB/DIP Updated address and MagAlign.

-07_A 8/05 GB/DIP Added -221, -223, -225 and -227 models.

-07_B 2/07 MPS Added Usage Clause

-07_C 8/07 MPS BIT Messages Updated

-08_A 11/09 PAL Added models -320 through -327 to

Revision History

time to 90 seconds

numbers -222 and -226. Updated the
installation drawing to reflect new models.

external aiding.

Updated MagAlign.

support improved dynamic response and
velocity aiding performance, and to
include MagAlign auto-leveling

1312

per ECO

-09_A 12/10 AP Updated w/ MEMSIC logo and address
per ECO 1886

0 WARNING

This product has been developed by MEMSIC exclusively for commercial applications. It has not been tested for, and MEMSIC makes no
representation or warranty as to conformance with, any military specifications or that the product is appropriate for any military application or
end-use. Additionally, any use of this product for nuclear, chemical, biological weapons, or weapons research, or for any use in missiles,
rockets, and/or UAV's of 300km or greater range, or any other activity prohibited by the Export Administration Regulations, is expressly
prohibited without the written consent of MEMSIC and without obtaining appropriate US export license(s) when required by US law. Diversion
contrary to U.S. law is prohibited.

©2010 MEMSIC, Inc. All rights reserved. Information in this document is subject to change without notice.
MEMSIC and SoftSensor are registered trademarks and AHRS500GA-[] is a trademark of MEMSIC, Inc. Other pr oduct and trade names are trademarks or

registered trademarks of their respective holders.

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AHRS500GA-[] Series Operator’s Manual

Table of Contents

1 Introduction.................................................................................................................................................................................1

1.1 The AHRS500GA-[] Series Motion and Attitude Sensing Units........................................................................................1

2 Package Contents........................................................................................................................................................................1

3 AHRS500GA-[] Description ......................................................................................................................................................2

3.1 AHRS500GA-[] Coordinate System...................................................................................................................................2

3.2 Connections ........................................................................................................................................................................2

3.2.1 I/O Cable.....................................................................................................................................................................3

3.2.2 Power Input and Power Input Ground ........................................................................................................................3

3.2.3 Case Ground ...............................................................................................................................................................3

3.2.4 Serial Data Interface ...................................................................................................................................................3

3.2.5 BIT Status Output Pin.................................................................................................................................................4

3.2.6 Magnetometer alignment Input Pin.............................................................................................................................4

3.2.7 No Connection............................................................................................................................................................4

3.3 Measurements.....................................................................................................................................................................5

3.3.1 Attitude and Heading..................................................................................................................................................5

3.3.2 Sensor Measurements .................................................................................................................................................5

3.3.3 BIT Processing............................................................................................................................................................5

3.4 Commands.......................................................................................................................................................................... 6

3.5 Data Packet Format.............................................................................................................................................................7

3.6 Timing.................................................................................................................................................................................7

3.7 Magnetic Heading...............................................................................................................................................................8

3.8 External Velocity Input (models -22x and higher)..............................................................................................................8

4 AHRS500GA-[] Operation.........................................................................................................................................................9

4.1 Normal Operation...............................................................................................................................................................9

4.2 Alignment Operation ..........................................................................................................................................................9

5 Viewing AHRS500GA-[] Data with GyroView.......................................................................................................................10

5.1 GyroView Computer Requirements..................................................................................................................................10

5.2 Install GyroView...............................................................................................................................................................10

5.3 Connections ......................................................................................................................................................................10

5.4 Setup GyroView ...............................................................................................................................................................10

5.5 Take Measurements..........................................................................................................................................................11

6 Limitations................................................................................................................................................................................11

6.1 Installation ........................................................................................................................................................................11

6.2 Alignment.........................................................................................................................................................................11

6.3 Operation in Magnetic Environment.................................................................................................................................11

6.4 Range Limitations.............................................................................................................................................................11

7 AHRS500GA-[] Installation .....................................................................................................................................................12

8 Warranty and Support Information...........................................................................................................................................13

8.1 Customer Service..............................................................................................................................................................13

8.2 Contact Directory..............................................................................................................................................................13

8.3 Return Procedure..............................................................................................................................................................13

8.3.1 Authorization............................................................................................................................................................13

8.3.2 Identification and Protection.....................................................................................................................................13

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8.3.3 Sealing the Container................................................................................................................................................13

8.3.4 Marking.....................................................................................................................................................................13

8.3.5 Return Shipping Address ..........................................................................................................................................14

8.4 Warranty ...........................................................................................................................................................................14

9 Appendix A. Mechanical Specifications...................................................................................................................................15

10 Appendix B. AHRS500GA-[] Out put Q ui c k R eference.......................................................................................................17

11 Appendix C. Velocity Input Packet Format..........................................................................................................................18

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About this Manual

The following annotations have been used to provide additional information.

; NOTE

Note provides additional information about the topic.

; EXAMPLE

Examples are given throughout the manual to help the reader understand the terminology.

3 IMPORTANT

This symbol defines items that have significant meaning to the user

0 WARNING

The user should pay particular attention to this symbol. It means there is a chance that physical harm could happen to either the
person or the equipment.

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AHRS500GA-[] Series Operator’s Manual

1 Introduction

1.1 The AHRS500GA-[] Series Motion and Attitude Sensing Units

This manual explains the use of the AHRS500GA-[] Series of products, nine-axis measurement system designed to measure
stabilized pitch, roll and yaw angles in a dynamic environment.

The AHRS500GA-[] is a nine-axis measurement system that combines linear accelerometers, rotational rate sensors, and
magnetometers. The AHRS500GA-[] uses the 3-axis accelerometer and 3-axis rate sensor to make a complete measurement of
the dynamics of your system. The addition of a 3-axis magnetometer also allows the AHRS500GA-[] to make a true
measurement of magnetic heading.

The AHRS500GA-[] is the solid-state equivalent of a vertical gyro/artificial horizon display combined with a directional gyro.
The AHRS500GA-[] series units are low power, fast turn on, reliable and accurate solutions for a wide variety of stabilization and

measurement applications.
See Table 3 for the serial interface for each AHRS500GA-[] model. Data is streamed continuously.
MEMSIC AHRS500GA-[] units employ onboard digital processing to compensate for deterministic error sources within the unit

and to compute attitude information. The AHRS500GA-[] units accomplish these tasks with an analog to digital converter and
high performance Digital Signal Processors.

The AHRS500GA-[] uses angular rate sensors and linear acceleration sensors that are micro-machined devices. The three angular
rate sensors consist of vibrating ceramic plates that utilize the Coriolis force to output angular rate independently of acceleration.
The three MEMS accelerometers are surface micro-machined silicon devices that use differential capacitance to sense
acceleration. Solid-state MEMS sensors make the AHRS500GA-[] both responsive and reliable. The magnetic sensors are state­of-the-art miniature fluxgate sensors. Fluxgate sensors make the AHRS500GA-[] sensitive and responsive, with better
temperature performance than other technologies such as magneto-resistive sensors.

The AHRS500GA-[] Series of products utilize a sophisticated Kalman filter algorithm to allow the unit to track orientation
accurately through dynamic maneuvers. The Kalman filter will automatically adjust for changing dynamic conditions without
any external user input. No user intervention or configuration is required at power-up.

2 Package Contents

In addition to your AHRS500GA-[] sensor product and the AHRS500GA-[] Series Operator’s Manual, you should have:

• 1 CD with AHRS500 Installation MagAlign Software

AHRS500 Installation MagAlign Software graphically displays the AHRS500GA-[] output and provides step-by-step
alignment instructions on a PC running Microsoft® Windows™. You can also download this software from MEMSIC’s
web site at http://www.xbow.com.

• 1 Digital Signal Alignment/Maintenance Cable.

This links the AHRS500GA-[] directly to a serial port. Only transmit, receive, power, ground and magnetometer
alignment pins are used. The magnetometer alignment switch is located on a cable stub attached to the PC connector
end.

• 1 set of Mounting Hardware

Non-magnetic fasteners are provided to mount the AHRS500GA-[].

• AHRS500GA-[] Installation Manual

This contains the installation and alignment information for the AHRS500GA-[] model type ordered.

• AHRS500GA-[] Installation Drawing

• AHRS500GA-[] Installation Wiring Diagr am

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3 AHRS500GA-[] Description

3.1 AHRS500GA-[] Coordinate System

The AHRS500GA-[] uses the following coordinate system. With the connector facing you, and the mountin g plate down, the axes
are defined as:

X-axis – from face with connector through the AHRS500GA
Y-axis – along the face with connector from left to right
Z-axis – along the face with the connector from top to bottom

This is the default configuration for the generic AHRS500GA-[] model. Other coordinate frame orientations are supported given
the model type purchased, and these will be reflected in the label as well as through the model configuration number. The axes
form an orthogonal right-handed coordinate system. Acceleration is positive when it is oriented towards the negative side of the
coordinate axis. For example, with the AHRS500GA-[] sitting on a level table, it will measure zero g along the x- and y-axes and
+1 g along the z-axis. Gravitational acceleration is directed downward, and thus will be defined as positive for the AHRS500GA­[] z-axis.

The angular rate sensors are aligned with these same axes. The rate sensors measure angular rotation rate around a given axis.
The rate measurements are labeled by the appropriate axis. The direction of a positive rotation is defined by the right-hand rule.
With the thumb of your right hand pointing along the axis in a positive direction , your fingers curl around in the positive rotation
direction. For example, if the AHRS500GA-[] is sitting on a level surface and you rotate it clockwise on that surface, this will be
a positive rotation around the z-axis. The x- and y-axis rate sensors would measure zero angular rates, and the z-axis sensor
would measure a positive angular rate.

The magnetic sensors are aligned with the same axes definitions and sign as the linear accelerometers.
Pitch is defined positive for a positive rotation around the y-axis (pitch up). Roll is defined as positive for a positive rotation

around the x-axis (roll right). Yaw is defined as positive for a positive rotation around the z-axis (turn right).
The angles are defined as standard Euler angles using a 3-2-1 system. To rotate from the body frame to an earth-level frame, roll

first, then pitch, and then yaw.

3.2 Connections

The AHRS500GA-[] has a male DB-15 connector. The signals are as shown in Table 1.

Table 1 Connector Pin Assignments

Pin Signal Electrical Specifications

1 RS-232 Transmit +/- 4.5 VDC min wrt power ground.
2 RS-232 Receive +/- 25 VDC max wrt power ground.
3 VDC Power Input 10-40 VDC normal, 9VDC emergency
4 Power Input Ground
5 No connection Do not connect
6 No connection Do not connect
7 RS-422 Transmit + A
8 RS-422 Transmit – A

2.0 VDC differential output (min) into 100 ohms. Common mode output voltage,
3VDC max.

9 Signal Ground Capacitive coupling to internal system ground. Should be connected to user’s

system ground to reduce RS-232 and RS-422 signal noise.
10 Factory mode pin Factory reserved; do not connect
11 Factory mode pin Factory reserved; do not connect
12 Magnetometer alignment input (hard

and soft iron cal)

Active: Short to power ground.

Inactive: Open circuit. (Internally pulled to +3.3VDC through 10Kohm resistor)
13 Hardware BIT Status Open collector, requires user pull-up resistor. Max pull-up voltage: +15VDC

Max current sink: 10mA.

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14 RS-422 Receive + A

Common mode input voltage ra nge: 3 VDC wrt p ower ground.

15 RS-422 Receive – A

N/A Case Ground Electrically connected to I/O connector shell

3.2.1 I/O Cable

The user must provide a shielded cable with the shield connected to the I/O connector shell in order to provide the required EMI
protection. The cable sent with the unit is intended to provide the user with the ability to perform a magnetome

ter alignment, and

provide routine magnetometer alignment maintenance of the system, and will not pro vide adequate shielding.

3.2.2 Power Input and Power Input Ground

The AHRS500GA-[] power requirements are described in the table below. It is designed to o
or 28VDC aircraft power system and me .

ets all DO-160D, part 16, category B requirements

perate with either a nominal 14VDC

Table 2 E al Power Input Requirements

Item

Requirement

lectric

AHRS500

GA-[] specification

1. pply 10-40 VDC Input Su
voltage

2. ly

Input Supp 1
Current

Amp (max)

3.2.3 Case Ground

The case is electrically connected to the I/O connector shell. The shell should be electrically connected to the user’s cable shi eld.
The case is isolated from the Power Input Ground, and should be bolted to a good conducting surface that is grounded.

3.2.4 Serial Data Interface

The interface specification is a factory configurable RS-422 or RS-232, also with factory configurable baud rates (see table
below) depending on

the model configuration chosen. Data output is continuous at a fixed frequency dependant on the baud rate

(see table 3 below).

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AHRS500GA-[] Series Operator’s Manual

Table 3 Supported BAUD Rates and Output Rates

Model :

Interface BAUD

AHRS500GA

-200 RS-232 38400 100 AFT

-201 RS-232 38400 100 FORWARD

-202 RS-232 9600 25 AFT

-203 RS-232 9600 25 FORWARD

-204 RS-232 9600 25 AFT

-205 RS-232 9600 25 FORWARD

-206 RS-422 38400 100 AFT

-207 RS-422 38400 100 FORWARD

-220* RS-232 38400 100 AFT

-221* RS-232 38400 100 FORWARD

-222* RS-232 9600 25 AFT

-223* RS-232 9600 25 FORWARD

-224* RS-232 9600 25 AFT

-225* RS-232 9600 25 FORWARD

-226* RS-422 38400 100 AFT

-227* RS-422 38400 100 FORWARD

-320* RS-232 38400 100 AFT

-321* RS-232 38400 100 FORWARD

-322* RS-232 9600 25 AFT

-323* RS-232 9600 25 FORWARD

-324* RS-232 9600 25 AFT

-325* RS-232 9600 25 FORWARD

-326* RS-422 38400 100 AFT

*

Refer to Appendix C for input velocity data packet format

-327* RS-422 38400 100 FORWARD

Rate

Output
Rate

Connector
Facing

3.2.5 BIT Status Output Pin

The BIT status output pin will become active high if the system is experiencing a failure. The BIT is an open collector signal and
requires a pull-up resistor for proper operation.

3.2.6 Magnetometer alignment Input Pin

The AHRS500GA-[] has an input pin to control the magnetometer hard-iro n alignment function. When this pin is active (low) the
unit will collect the data necessary for magnetometer alignment. When it becomes inactive, the alignment data shall be used to
compute the hard and soft iron compensation values. During normal operation, no connection should be made to this pin; this pin
shall be tied high internally with a pull-up resistor. This feature has been added as a means to perform a Hard Iron/Soft Iron
alignment without sending the alignment commands to the unit. Please see the AHRS500GA-[] Installation Manual for a
complete explanation of the Hard Iron/Soft Iron alignment process, and how this pin can be used as a means of implementing the
alignment.

3.2.7 No Connection

During normal operation of the AHRS500GA-[], no connection is made to the factory test pin. This pin has an internal pull-up
mechanism and must have no connection for the AHRS500GA-[] to operate properly.

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3.3 Measurements

The AHRS500GA-[] Series is designed to operate as a complete attitude and heading reference system. See the “Data Packet
Format” section for the actual structure of the data packet.

3.3.1 Attitude and Heading

The AHRS500GA-[] acts as a complete attitude and heading reference system and outputs the stabilized pitch, roll, an d yaw
angles along with the angular rate, acceleration, and magnetic field information. The angular rate, acceleration, and magnetic
field values are calculated as described in the sensor section.

The Kalman filter operates in angle mode to track the rate sensor bias and calculate the stabilized roll, pitch, and yaw angles.
The AHRS500GA-[] uses the angular rate sensors to integrate over your rotational motion and find th e actual pitch, roll, and yaw

angles. The AHRS500GA-[] uses the accelerometers to correct for rate sensor drift in the vertical angles (pitch and roll); the
AHRS500GA-[] uses the magnetometers to correct for rate sensor drift in the yaw angle. This is the modern equivalent of an
analog vertical gyro that used a plumb bob in a feedback loop to keep the gyro axis stabilized to vertical. The AHRS500GA-[]
takes advantage of the rate gyros’ sensitivity to quick motions to maintain an accurate orientation when accelerations would
otherwise throw off the accelerometers measurement of the AHRS500GA-[] orientation relative to gravity; the AHRS500GA-[]
then uses the accelerometers to provide long term stability to keep the rate gyro drift in check.

The AHRS500GA-[] uses a sophisticated Kalman filter algorithm to track the bias in the rate sensors. This allows the
AHRS500GA-[] to use a very low effective weighting on the accelerometers when the AHRS500GA-[] is moved. This makes the
AHRS500GA-[] very accurate in dynamic maneuvers.

The AHRS500GA-[] outputs the stabilized pitch, roll and yaw angles in the digital data packet in angle mode. To convert the
digital data to angle, use the following relation:

15

angle = data*(SCALE)/2

where angle is the actual angle in degrees (pitch, roll or yaw), data is the signed integer data output in the data packet, and
SCALE is a constant. SCALE = 180° for roll, pitch and yaw.

3.3.2 Sensor Measurements

The analog accelerometer and gyro sensors are sampled, converted to digital data, temperature compensated, corrected for
misalignment, and scaled to engineering units. The digital data represents the actual value of the quantities measured. A
calibration table for each sensor is stored in the AHRS500GA-[] non-volatile memory. The data is sent as signed 16-bit 2’s
complement integers. To convert the acceleration data into G’s, use the following conversion:

15

accel = data*(10 * 1.5)/2

where accel is the actual measured acceleration in G’s, data is the digital data sent by the AHRS500GA, and 10 is the G Range
for your AHRS500GA. (The data is scaled so that 1 G = 9.80 m s

-2

.) This maximum G range is a default value.

To convert the angular rate data into degrees per second, use the following conversion:

rate = data*(800*1.5)/2

15

where rate is the actual measured angular rate in °/sec, data is the digital data sent by the AHRS500GA, and 800 is the Angular
rate Range of the AHRS500GA. This maximum angular rate is a default value.

3.3.3 BIT Processing

The BIT message in each packet provides comprehensive information into system health. The following information is supplied
in the BIT byte fields of the data packet. Table 4 contains the actual bit definition present in the two-byte output BIT field in the
angle mode data packet (see section 3.5 below).

Table 4 BIT Message Definition

Bit BIT Data Description

0 Hard Failure 0: No hard failure

1: An unrecoverable failure has been detected

1 Soft Failure 0: No soft failure

1: A soft failure has been detected. If the soft failure lasts for more than 4500
data packets the Hard Failure bit is turned on and the Soft Failure bit is

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AHRS500GA-[] Series Operator’s Manual

permanently on.
2 Reserved
3 Power Failure 0: No power failure

1: A power loss has been detected and the system is running on back-up

power. Power loss will occur within 200 msec.
4 Comm Error 0: No serial port communication failure has been detected.

1: A serial port communications failure has been detected such as overrun,

parity.
5 Reboot Detect 0: No warm reboot of the processor has been detected.

1: A warm processor reboot was detected possibly due to a watchdog timeout

or low-power setting.
6 Calibration Failure 0: Calibration table in flash memory is correct.

1: A bad calibration table in flash memory has been detected.
7* External Aiding Comm Status 0: Receiving and processing valid external aiding data packets

1: External aiding data not present or bad external aiding data
8 Coordinated Turn

Detect

0: Unit is not executing a coordinated turn

1: Unit is executing a coordinated turn

9 Magnetometer Align Status

(MSB)

10: Remote magnetometer or internal magnetometer hard iron/soft iron

alignment in progress

11: Remote magnetometer heading offset alignment in progress
10 Algorithm Status 0: Full accuracy data

1: Not ready, waiting for power-up, post gyro saturation, or initialization

11 Magnetometer Align Status

(LSB)

00: No magnetometer alignment being performed

01: Remote magnetometer leveling in progress
12 Magnetometer Leveling Status 0: Remote magnetometer leveling valid

1: Remote magnetometer leveling invalid
13 Hardiron/Softiron Valid 0: Magnetometer hard iron/soft iron alignment valid

1: Magnetometer hard iron/soft iron alignment invalid
14 Heading Offset 0: Remote magnetometer heading offset alignment is valid

1: Remote magnetometer heading offset alignment is invalid
15* Remote Magnetometer Comm

Status

0: Communication with Remote Magnetometer valid (processing data

packets)

1: Communication with Remote Magnetometer invalid (no data packets being

processed)

*

External aiding AND Remote magnetometer do not apply to models -200, -201, -202 , -203, -204, -205, -206 and -207

3.4 Commands

The AHRS500GA-[] does not have a command structure. The default serial interface is provided in table 3 with serial port
settings of 8 data bits, 1 start bit, 1 stop bit, no parity, and no flow control.

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3.5 Data Packet Format

In general, the digital data representing each measurement is sent as a 16-bit number (two bytes). The data is sent MSB first then
LSB.

Table 5 AHRS500GA-[] Series Data Packet Format

Byte Data

0 Header (0xAA)
1 Header (0x55)
2 Roll Angle (MSB)
3 Roll Angle (LSB)
4 Pitch Angle (MSB)
5 Pitch Angle (LSB)
6 Heading Angle (MSB)
7 Heading Angle (LSB)
8 Roll Angular Rate (MSB)

9 Roll Angular Rate (LSB)
10 Pitch Angular Rate (MSB)
11 Pitch Angular Rate (LSB)
12 Yaw Angular Rate (MSB)
13 Yaw Angular Rate (LSB)
14 X-Axis Acceleration (MSB)
15 X-Axis Acceleration (LSB)
16 Y-Axis Acceleration (MSB)
17 Y-Axis Acceleration (LSB)
18 Z-Axis Acceleration (MSB)
19 Z-Axis Acceleration (LSB)

Model Number (MSB)

20

Model Number (LSB)

21
22 BIT (MSB)
23 BIT (LSB)
24 Checksum (MSB)
25 Checksum (LSB)

These numbers are sent as a 16-bit signed integer in 2's complement format. The data is sent as two bytes, MSB first then LSB.
Each data packet will begin with a two-byte header (hex AA 55) and end with a two-byte checksum. The checksum is calculated

in the following manner:

1. Sum all packet contents except header and checksum.

2. Divide the sum by hex FFFF.

3. The remainder should equal the checksum.

The packet also contains the model type configuration number, and the BIT word output. Please refer to section 3.3.3 for details
about the BIT word processing.

3.6 Timing

The AHRS500GA-[] data output rate is set based on the model configuration chosen. See table 3 for currently supported output
rates. Depending on the configuration chosen, the system output sample rate can be set to a different constant value.

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In some applications, using the AHRS500GA-[]’s digital output requires a precise understanding of the internal timing of the
device. The processor internal to the AHRS500GA-[] runs in a loop - collecting data from the sensors, processing the data, and
then collecting more data. The data is reported to the user through a parallel process.

The unit goes through three processes in one data cycle. First, the sensors are sampled. Second, the unit processes the data for
output. After processing the data, the AHRS500GA-[] will make another measurement while presenting the current measurement
for output. Third, the unit actually transfers the data out over the RS-232 port.

3.7 Magnetic Heading

Magnetic north is the direction toward the magnetic north pole; true north is the direction towards the true North Pole.
The AHRS500GA-[] yaw angle output is referenced to magnetic north. The direction of true north will vary from magnetic north

depending on your position on the earth. The difference between true and magnetic north is called declination or magnetic
variance. You will need to know your declination to translate the AHRS500GA-[] magnetic heading into a heading referenced to
true north.

3.8 External Velocity Input (models -22x and higher)

An external velocity input is accepted (when available) to provide im proved accuracy on high performance aircraft capable of
sustained acceleration and deceleration. The AHRS500GA-22x models (and higher) include a communications interface
designed to listen for external velocity sensor information. This interface determines when the velocity information is available on
the input port (RS232 UART), parses the velocity information, and makes the airspeed data available for use in the attitude
algorithm. In the event that the external velocity data is not present, or the external velocity data fails after correct operation, the
algorithm reverts back to the standard algorithm defined above. The external velocity input packet format is defined in Appendix
C.

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4 AHRS500GA-[] Operation

4.1 Normal Operation

The AHRS500GA-[] is configured to output data continuously wh en power is applied. The AHRS500GA-[] does not recognize
any input serial commands. A magnetic alignment process must be completed before use of the AHRS500GA-[]. See the
AHRS500GA-[] Installation Manual for specific instructions. The AHRS500GA-[] requires a 90 second initialization period after
power is applied before the output data is valid. Valid data is indicated by the BIT status word having all bits cleared to zero,
indicating no BIT failures, a valid magnetometer alignment, and completion of initialization.

4.2 Alignment Operation

The AHRS500GA-[] can be commanded to perform a hard/soft iron alignment for the magnetometers using the procedure in the
AHRS500GA-[] Installation Manual. Data supplied during normal operation will not be available and the data output should not
be used for flight purposes.

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5 Viewing AHRS500GA-[] Data with GyroView

MEMSIC includes GyroView software to allow you to directly view the AHRS500GA-[] data.

5.1 GyroView Computer Requirements

The following are minimum capabilities that your computer should have to run GyroView successfully:

• CPU: Pentium-class

• RAM Memory: 32MB minimum, 64MB recommended

• Hard Drive Free Memory: 15MB

• Operating System: Window s 95 , 98 , NT4, 2000, XP

5.2 Install GyroView

To install GyroView in your computer:

1. Insert the CD “Support Tools” in the CD-ROM drive.

2. Find the GyroView folder. Double click on the setup file.

3. Follow the setup wizard instructions. You will install GyroView and a LabVIEW Runtime Engine. You will need both

these applications.

If you have any problems or questions, you may contact MEMSIC directly.

5.3 Connections

The AHRS500GA-[] is shipped with an alignment/maintenance cable to connect the AHRS500GA-[] to a PC communications
port.

1. Connect the 15-pin end of the digital signal alignment/maintenance cable to the port on the AHRS500GA-[].

2. Start the PC before connecting the alignment/maintenance cable to the serial port of your computer. Some versions of

Windows treat a serial connection at boot time as a signal that a serial mouse is connected to the serial port. The serial
mouse driver will be loaded and the AHRS500GA-[] output will drive the cursor around the screen.

3. Connect the 9-pin end of the alignment/maintenance cable to the serial port of your computer.

4. Connect the 15-pin end of the digital signal alignment/maintenance cable to the aircraft mating cable.

5. Bolt the base of the unit to a grounded surface. A good ground is required for EMI and lightning over-voltage

protection.

0 WARNING

Do not reverse the power leads! Applying the wrong power to the AHRS500GA-[] can damage the unit.

5.4 Setup GyroView

With the AHRS500GA-[] connected to your PC serial port and powered, open the GyroView software (Rev 2.3 or later).

1. GyroView should automatically detect the AHRS500GA-[] and display the serial data connectio n information.

2. If GyroView does not connect, check that you have the correct COM port selected. You find this under the “DMU”

menu.

3. Select the type of display you want under the menu item “Windows”. Graph displays a real time graph of all the

AHRS500GA-[] data; FFT displays a Fast-Fourier transform of the data; Navigation shows an artificial horizon display.

4. You can log data to a file by entering a data file name. You can select the rate at which data is saved to disk.

5. If the status indicator says, “Connected”, you’re ready to go. If the status indicator doesn’t say connected, check the

connections between the AHRS500GA-[] and the computer; check the power; check the serial COM port assignment on
your computer.

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AHRS500GA-[] Series Operator’s Manual

5.5 Take Measurements

Once you have configured GyroView to work with your AHRS500GA-[], pick what kind of measurement you wish to see.
“Graph” will show you the output you choose as a strip-chart type graph of value vs. time. “FFT” will show you a real-time Fast­Fourier transform of the output you choose. “Navigation” will show an artificial horizon and the stabilized pitch and roll output
of the AHRS500GA-[].

Let the AHRS500GA-[] warm up for 90 seconds when first turned on. This allows the Kalman filter to estimate the rate sensor
biases. Now you’re ready to use the AHRS500GA-[]!

6 Limitations

6.1 Installation

The AHRS500GA-[] must be mounted in accordance with the procedures outlined in the AHRS500GA-[] Installation Manual.
The AHRS500GA-[] must be mounted in a location with limited magnetic material near the unit. Refer to the installation manual
for detailed instructions.

6.2 Alignment

The AHRS500GA-[] must successfully complete a hard iron alignment to reach full accuracy. Refer to the AHRS500GA-[]
installation manual for detailed instructions.

6.3 Operation in Magnetic Environment

Introduction of large ferrous or magnetic material objects close to the AHRS500GA-[], after alignment, will affect the heading
performance. Maintain at least 24 inches of distance between moving ferrous metal or magnetic material and the AHRS500GA­[].

6.4 Range Limitations

The internal sensors in the AHRS500GA-[] are limited to maneuvers of less than 200 deg/sec and less than 10 Gs acceleration in
bank, pitch, and heading. Over range of a sensor is indicated in the data packet message to the display system. Over range will
start a new initialization cycle of the AHRS500GA-[] and will require 90 seconds of straight and level flight to reinitialize the
AHRS500GA-[].

The AHRS500GA-[], like all magnetometer and magnetic compass-based systems, will not perform properly at the magnetic
North and South Poles.

The AHR500GA-[] will not operate properly in low gravitational fields and magnetic fields encountered during space flight.

Doc# 7430-0060-09 Rev. A Page 11

AHRS500GA-[] Series Operator’s Manual

7 AHRS500GA-[] Installation

Refer to the AHRS500GA-[] Installation Manual (Do c# 7410-0001-08) for detailed mounting instructions for the AHRS500GA­[].

Doc# 7430-0060-09 Rev. A Page 12

AHRS500GA-[] Series Operator’s Manual

8 Warranty and Support Information

8.1 Customer Service

As a MEMSIC customer you have access to product support services, which include:

• Single-point return service

• Web-based support service

• Same day troubleshooting assistance

• Worldwide MEMSIC representation

• Onsite and factory training available

• Preventative maintenance and repair programs

• Installation assistance available

8.2 Contact Directory

United States: Phone: [phone] (8 AM to 5 PM PST)
Fax: [phone] (24 hours)
Email: [e-mail]
Non-U.S.: Refer to website www.memsic.com

8.3 Return Procedure

8.3.1 Authorization

Before returning any equipment, please contact MEMSIC to obtain a Returned Material Authorization number (RMA).
Be ready to provide the following information when requesting an RMA:

• Name

• Address

• Telephone, Fax, Email

• Equipment Model Number

• Equipment Serial Number

• Installation Date

• Failure Date

• Fault Description

• Will it connect to GyroView?

8.3.2 Identification and Protection

If the equipment is to be shipped to MEMSIC for service or repair, please attach a tag TO THE EQUIPMENT, as well as the
shipping container(s), identifying the owner. Also indicate the service or repair required, the problems encountered, and any
other information considered valuable to the service facility such as the list of information provided to request the RMA number.

Place the equipment in the original shipping container(s), making sure there is adequate packing around all sides of the
equipment. If the original shipping containers were discard e d, use heavy boxes with adequate padding and pr ot ect i on.

8.3.3 Sealing the Container

Seal the shipping container(s) with heavy tape or metal bands strong enough to handle the weight of the equipment and the
container.

8.3.4 Marking

Please write the words, “FRAGILE, DELICATE INSTRUMENT” in several places on the outside of the shipping container(s).
In all correspondence, please refer to the equipment by the model number, the serial number, and the RMA number.

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AHRS500GA-[] Series Operator’s Manual

8.3.5 Return Shipping Address

Use the following address for all returned products:

MEMSIC, Inc.
1751 McCarthy Blvd.
Milpitas, CA 95035
Attn: RMA Number (XXXXXX)

8.4 Warranty

The MEMSIC product warranty is one year from date of shipment.

Doc# 7430-0060-09 Rev. A Page 14

AHRS500GA-[] Series Operator’s Manual

9 Appendix A. Mechanical Specifications

Refer to the AHRS500GA-[] Installation drawing, 7420-0001-0 1, below for the mechanical specifications.

7420-0001-01

D

BY

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1

 fiflfl



ECO#

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DATE

 



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REVISIONS

C

B

2

DESCRIPTION

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

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

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REV

ZONE

34

NOTES UNLESS OTHERWISE STATED:

1) INTERPRET DWG. PER ANSI Y14.5M-1994

2) CONTROLLING DIMENSION: INCHE S

3) FINISH: GOLD ALODINE (ON BASE AND COVER)

15 POSITION MALE "D" CONNECTOR

5) TO FASTEN THE AHRS TO THE AIRCRAFT, IT IS

RECOMMENDED TO USE THE FASTENERS

PROVIDED . THEY ARE INTENDED FOR A SHELF

THAT IS APPROXIMATELY .050 INCH THICK.

AT LEAST ONE .063 INCH THICK WASHER MUST BE

USED IN EACH FASTENER STACK. IF THE WASHER

IS PLACED UNDER THE HEAD OF THE BOLT, PUT

THE WASHER SIDE WITH THE STAMPING RADIUS

AGAINST THE UNDERSIDE OF THE BOLT HEAD.

IF THE PROVIDED FASTENERS ARE NOT USED,





4

POSITION 8

THEN FASTENERS MADE OF MATERIAL WITH LITTLE

POSITION 15

OR NO MAGNETIC PERMEABILITY MUST BE USED.

1 RS-232 TRANSMIT

2 RS-232 RECEIVE

3 VDC POWER INPUT

4 P OWER INP UT GROUND

5 NO C ONNECTION

6 NO C ONNECTION

7 RS-422 TRANSMIT +A

8 RS-422 TRANSMIT -A

9 S IGNAL GROUND

10 FACTORY MODE PIN

Position # SIGNAL

11 FACTORY MODE PIN

A

4145 N. First Street

San Jose, CA

F

REV

95134

SHEET 1 of 2

1

7420-0001-01

AHRS500 SERIES

MEMSIC

DATE

12 MAGNETOMETER ALIGNMENT INPUT

APPROVALS

13 HARD WARE BIT STATUS

14 RS- 422 REC EIVE +A

15 RS-422 RECEIVE -A

TOLERANCES ARE:

DIMENSIONS ARE IN INCHES

UNLESS OTHERWISE SPECIFIED



DWN

SCALE 1:2

INSTALLATION DRWG

TITLE

B

SIZE DWG. NO.

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ANGLES

2 PL

3 PL

2

CHK

APRVD

APRVD

APRVD

1

.040

3

.020

DO NOT SCALE DRAWING

MATERIAL:

4

DETAIL A

SCALE 3 : 2

5

POSITION 1

.0001 PINS

.344

HOLE AND SLOT TO MATE

TO .2502

6

5.905

5.250

1.220

3.600

7

POSITION 9

.290

4 x

1.250

1.750

4.660

4.86

A

4.530

4.82

EXCEPT AS MAY BE OTHERWISE PROVIDED BY CONTRACT

THIS DRAWING OR SPECIFICA TION IS THE PROPRIETARY

PROPERTY OF CROSSBOW TECHNOLOGY INC. IT IS ISSUED

IN STRICT CONFIDENCE AND SHALL NOT BE REPRODUCED

OR COPIED OR USED (PARTIALLY OR WHOL LY) IN ANY

MANNER WITHOUT PRIOR EXPRESS WRITTEN AUTHORIZA-

TION OF CROSSBOW TECHNOLOGY INC.

5

.375

6

7

4

.688

8

#6-32 UNC 2B THD THRU

LOCATION FOR OPTIONAL

D

C

GROUND WIRE

B

A

8

Doc# 7430-0060-09 Rev. A Page 15

AHRS500GA-[] Series Operator’s Manual

Doc# 7430-0060-09 Rev. A Page 16

AHRS500GA-[] Series Operator’s Manual

10 Appendix B. AHRS500GA-[] Output Quick Reference

10 is the G-range of the accelerometers. This is the default maximum range of the accelerometers.
800 is the rate range of the rate sensors. This is the default maximum range of the gyros.

Digital Output Conversion
Data is sent as 16-bit signed integer.

Acceleration

Accel (G) = data * 10 * 1.5/2

15

Rate Magnetic Field
Rate (°/s) = data * 800 * 1.5/2

15

Conversion

Angle (°) = data * 180/2

Mag (Gauss) = data * 1.25 * 1.5/2

15

15

Doc# 7430-0060-09 Rev. A Page 17

AHRS500GA-[] Series Operator’s Manual

11 Appendix C. Velocity Input Packet Format

(For AHRS500GA-22x models and higher)

The following table describes the external aiding data packet format that is supported by the AHRS500GA-22x models (and
higher) via serial communication over the RS232 port. This data is sent over RS-232 port at 9600 baud, 8 data bits, no parity and
1 stop bit at the rate of 1 Hz.

Each data packet will begin with a two-byte header (hex AA 55) and end with a two-byte checksum. The checksum is calculated
in the following manner:

1. Sum all packet contents except header and checksum.

2. Divide the sum by hex FFFF.

3. The remainder should equal the checksum.

Table 6 AHRS Input Velocity Data Packet Format

Bytes Parameter Description

0-1 Header
2-19 Reserved
20-21

True
Airspeed

22-25

Pressure
Altitude

26-29

Reserved

30-31 Checksum

Packet Header (byte 0 = 0xAA, byte 1 = 0x55)
Factory Use Only
True Airspeed in the range of 0 - 2048 knots.
Resolution is 15 bits. Invalid indicated by a value

of 0xFFFF. Multiply this integer by (2048/ 2

15

) to
get knots true airspeed.
Pressure Altitude in the range of ±131072ft.

Resolution is 17 bits. Invalid indicated by a value
of 0xFFFFFFFF. Multiply this integer by (131072/

17

) to get feet of pressure altitude.

2
Factory Use Only

Two-byte sum of characters 2 through 29

Doc# 7430-0060-09 Rev. A Page 18

MEMSIC, Inc.
1751 McCarthy Blvd,
Milpitas CA 95035
Phone: [phone]
Fax: [phone]
Website: www.memsic.com