Honeywell HG4930 User manual

HG4930 INERTIAL
MEASUREMENT UNIT (IMU)
Installation and Interface Manual

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Honeywell Industrial Inertial Measurement Units
Electrical Interface
Asynchronous Protocol
General Description
Rotation Correction
Data Synchronization Signal
Normal Operation Mode Description
Mechanical Drawing and Installation
Export Guidance
Contact Us
Table of Contents
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Table 1. Connector Pin Description
Table 2. Input Power Specifications
Table 3. Asynchronous Control Message (0x01 Format)
Table 4. Asynchronous Control Message Field Status Word 1
Table 5. Asynchronous Control Message Field Status Word 2A
Table 6. Asynchronous Control Message Field Status Word 2B
Table 7. Asynchronous Inertial Message (0x02 Format)
Table of Tables

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Figure 1. Figure 1. Typical Cold (Left Figure)
and Hot Voltage/In-Rush Plots
Figure 2. Data Synchronization Signal Timing
Figure 3. Power Up Sequence
Figure 4. Accelerometer and Gyro Senor Mounting
Figure 5. Installation Drawing
Table of Figures

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Honeywell Industrial Inertial
Measurement Units
Honeywell produces no license required (NLR) Inertial Measurement Units (IMU) for industrial
applications including agricultural vehicles, robotics, survey, mapping, and stabilized systems.
These IMUs are designed for industrial application and can be used on air, land, and sea.
Honeywell began producing gyros in the 1940’s for the Honeywell C-1 autopilot and specically
began producing MEMS gyros and accelerometers in the early 2000’s. Honeywell’s IMUs
utilize proprietary Honeywell technology and leverage existing production and engineering
infrastructure. Honeywell has deep and long lasting relations with many commercial customers
and is carrying that philosophy and product pedigree into our NLR IMU line. Honeywell’s forward
looking product strategies will ensure that our NLR IMU’s will t your current and future needs.
The HG4930 IMU is a device which measures angular rates and linear accelerations in a body
mounted strapdown conguration. It will provide compensated incremental angle and velocity
data for navigation as wellas angular rates and linear accelerations for control. The data is reported
through a digital serial interface bus. The unit contains MEMS gyroscopes and accelerometers
as well as the electronics and software necessary to deliver precision control and navigation
information. The input axes form a right handed frame aligned with the IMU mounting frame.

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Table 1. Connector Pin Description
Electrical Interface
The pin assignments of the external system connector are shown below. Logic 0 corresponds
to the CMOS “low” logic state. Logic 1 corresponds to the CMOS “high” logic state.
PIN # SIGNAL NAME INPUT/OUTPUT & SIGNAL TYPE SIGNAL FUNCTION
1DGND Ground Digital Power and Signal Return
2+5VDC Input + 5 VDC Power – See Table 2
3No Connect
4No Connect
5No Connect
6RESET Input
CMOS Compatible Logic
Logic 1 applied for 7 milli-seconds will stop all
processing. Upon logic 0, the IMU will restart as if
power had been removed. No connection is required
(active pull down to logic 0).
7No Connect
8No Connect
9SER_DATA_OUT_H Output RS-422 Asynchronous High
10 SER_DATA_OUT_L Output RS-422 Asynchronous Low
11 DATA_SYNC_OUT_H Output RS-422 Data Sync High
12 DATA_SYNC_OUT_L Output RS-422 Data Sync Low
13 No Connect
14 No Connect
Table 2. Input Power Specifications
VOLTAGE
(VDC)
TOLERANCE MAX RIPPLE
(MV PP)
MAX RUN CURRENT
(AMP)
MAX CURRENT
(MA)
+5 ±5% 50 1.0 700
The 5V power application to the IMU must monotonically increase from 1 to 5 volts for proper IMU
start-up. The maximum current shown in Table 2 does not include in-rush current.
Figure 1 provides representative voltage and current plots at hot and cold for a ~ 2ms start time.
Worse case steady state current shown is ~500 mA (cold) and peak current shown is ~800 mA.
Unit typically draws < 400 mA in normal operation.
Figure 1. Typical Cold (Left Figure) and Hot Voltage/In-Rush Plots

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Asynchronous Protocol
General Description
The IMU supports the asynchronous RS-422 compatible protocol. Each Asynchronous output
frame will open with an IMU address byte that can be used as a synching byte.
The asynchronous 600/100 Hz data protocol is as specified in Table 3 – Control Message (0x01)
Format and Table 7 – Inertial Message (0x02) Format.
The start of sequential message transmissions is on the average 1/600 seconds ±0.01% apart,
with a repeating pattern of five control message transmissions followed by one inertial message
transmission.
The 600 Hz control data output consists of the angular rates, linear acceleration, and IMU status
words in message ID 0x01 and 0x02. The angular and linear data is filtered and sampled at 1800 Hz.
The 1800 Hz filtered angular and linear data is decimated for 600 Hz control data.
The 100 Hz navigation data output consists of incremental (or “delta”) angles and velocities in
message ID 0x02. The navigation data is unfiltered 1800 Hz sensor data which is summed to the
navigation data rate (100 Hz). Accurate attitude and position calculations require that all messages
be received and used.
The order of transmission is Least Significant (LS) bit first; LS byte first; LS 16 bit word first. Only
gyro, accelerometer, and temperature data is signed.
The transmit baud rate will be 1Mbits/sec with 1 start bit, 8 data bits, 1 stop bit, and no parity.

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Rotation Correction
The IMU shall subtract the “rotation correction” from the inertial delta-velocity components of
message ID 0x02 to allow direct integration of the synchronously sampled body-axis delta-angle and
delta-velocity elements. The “rotation correction” consists of one half of the sampled delta-angle
vector cross the sampled delta-velocity vector.
 ΔΘAsynchronous =ΔΘ SAMPLE
ΔVAsynchronous = ΔVSAMPLE - 0.5 * [ ΔΘSAMPLE X ΔVSAMPLE]
As a result of the subtraction, proper integration of local-vertical navigation components will
require update of the body-to-local-vertical attitude reference, transformation of the body-axis
delta-velocity components to the local-vertical frame followed by update of the local-vertical
attitude components.
Data Synchronization Signal
The Data Synchronization Signal shall be an active low pulse with the following characteristics:
• Pulse start is within +/- 1 microsecond of the most recent data sample event in
the Control data frame.
• Pulse width is 300 microseconds +/- 1 microsecond
The signal timing is shown in Figure 3 - Data Synchronization Signal Timing.
Figure 2. Data Synchronization Signal Timing
0x01 - 20 bytes - 200 us
0x02 - 44 bytes - 440 us
Transmit data
1666.67 us (One Data Frame)Time of
Validity
Start of
Data Transmission
Processing
Start
300us
Transmit data
~1.75
±0.015ms
1
0
300us
End of Data
transmission

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Table 3. Asynchronous Control Message (0x01 Format)
POSITION PARAMETER LENGTH
(BYTES)
LSB WEIGHT UNITS OR CONTENTS
1 IMU Address 1 N/A Constant 0x0E
2 Message ID 1 N/A Constant 0x01
3 Angular Rate X 2 2-20 * 600 rad/sec/LSB
4 Angular Rate Y 2 2-20 * 600 rad/sec/LSB
5 Angular Rate Z 2 2-20 * 600 rad/sec/LSB
6 Linear Acceleration X 2 2-14 * 600 0.3048 meters/sec2/LSB
7 Linear Acceleration Y 2 2-14 * 600 0.3048 meters/sec2/LSB
8 Linear Acceleration Z 2 2-14 * 600 0.3048 meters/sec2/LSB
9 Status 1 2 N/A See Table 4
10 Status 2A or 2B 2 N/A See Table 5 and 6
11 Checksum
Sum of all message data (positions
1…10 of this table), taken as 16 bit
words, and summed without regard for
rollover.
2N/A // this pseudo code illustrates the checksum
algorithm
u16sum = 0;
for (i=0; i<9; i++) // (20-2)/2=9
{ u16sum += u16_msg_array[i]; }
Checksum = u16_msg_array[9];
if (Checksum != u16sum) {checksum error}
Total Length 20
BIT DEFINITION NOTES
Bit 0-1 2 Bit Counter 00 01 10 11...
Bit 2-3 2 bit BIT-mode indicator 0=Power-up BIT
1=Continuous BIT
2-3 = Reserved
Bit 4 IMU 0=OK, 1=Failed
These fault monitors are aggregate and latched (continue after the failure
has stopped) but will only latch after a lower level test has failed. The
latching logic may require multiple consecutive failures before setting.
These latched failures are cleared after power up or reset.
Bit 5 Gyro
Bit 6 Accelerometer
Bits 7-10 Gyro Sensor 0=OK, 1=Failed
Bit 7 checks sensor voltage levels.
Bits 8-10 check that Gyros X, Y, and Z are individually functioning.
Bit 11-14 Reserved N/A
Bit 15 IMU OK 0=OK, 1=Failed
Table 4. Asynchronous Control Message Field Status Word 1

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Table 6. Asynchronous Control Message Field Status Word 2B
BIT DEFINITION NOTES
Bit 0-7 Accelerometer X Temperature LSB=1°C, Not Calibrated
Bits 8-14 Identical to Field Status Word 2A See Table 5
Bit 15 Status Word 2X flag 1=2B
Table 7. Asynchronous Inertial Message (0x02 Format)
POSITION PARAMETER LENGTH
(BYTES)
LSB WEIGHT UNITS OR CONTENTS
1 IMU Address 1 N/A Constant 0x0E
2 Message ID 1 N/A Constant 0x02
3-10 Control Data 16 N/A Contents same as Message 0x01
Positions 3-10.
11 Delta Angle X 4 2-33
radians/LSB
or equivalently,
radians/second/Hz/LSB
12 Delta Angle Y 4 2-33
13 Delta Angle Z 4 2-33
14 Delta Velocity X 4 2-27
0.3048 meters/sec/LSB
or equivalently,
0.3048 meters/sec2/Hz/LSB
15 Delta Velocity Y 4 2-27
16 Delta Velocity Z 4 2-27
17 Checksum
Sum of all message data (positions
1-16 of this table), taken as 16 bit
words, and summed without regard for
rollover.
2N/A // this pseudo code illustrates the
checksum algorithm
u16sum = 0;
for (i=0; i<21; i++) // (44-2)/2=21
{ u16sum += u16_msg_array[i]; }
Checksum = u16_msg_array[21];
if (Checksum != u16sum) {checksum
error}
Total Length 44
BIT DEFINITION NOTES
Bit 0-7 Software Version Number
Bit 8 Gyro Health 0=OK, 1=Failed
Bit 9 Start data flag 0=sensor data, 1=0x5555 data transmitted for synchronization
Bit 10 Process Test 0=OK, 1=Failed
Bit 11 Memory Test 0=OK, 1=Failed
Bit 12 Electronics Test (ASIC) 0=OK, 1=Failed
Bit 13 Gyro Health 0=OK, 1=Failed
Bit 14 Accelerometer Health 0=OK, 1=Failed
Bit 15 Status Word 2X flag 0=2A
Table 5. Asynchronous Control Message Field Status Word 2A

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Normal Operation Mode Description
The serial data interface is operational within 300 milliseconds after the last applied power form is
within the specified tolerances and the reset line is inactive.
The IMU transmits a fixed pattern 0x5555 (Hex) in place of Control sensor data and 0x55555555
(Hex) in place of Inertial sensor data until the completion of Power Up BIT.
The IMU completes Power Up BIT and report the results within 400 milliseconds after power is
within specified tolerances and IMU Reset is inactive.
Figure 3. Power Up Sequence
Supervisor Reset or
External (IMU) Reset
Released
Power
Applied
<= 40ms
Serial Data
No Data Fixed Data Pattern
Normal
Serial Data
< 260 ms
<= 260 ms
<= 400 ms
<= 440 ms
Time