User Manual

6 sensing.honeywell.com
Transportation Attitude Reference System
(TARS Series)
ISSUE B 32332897
6.0 CAN MESSAGES AND COMMUNICATION
TARS-IMU utilizes CAN J1939 protocol and message format to
report data. Please refer to J1939 specification and standards
for information regarding communication and implementing
CAN J1939 systems.
6.1 CAN J1939 Device Identification
The ID is a 4-byte value to identify the message being
transmitted.
• All J1939 messages are Ext CAN
• All messages have default priority
0 (lowest) <= priority <= 0x7 (highest)
• PDU formats < 0xF0 are peer to peer
PDU Specific is filled with destination address
• PDU formats >= 0xF0 are broadcast
PDU Specific further defines the message format
• PDU formats = 0xFF are global broadcast
• All J1939 messages end with the sending address in the last byte
Table 7. J1939 ID Format
Extended PDU SA
Ext
CAN
Reserved Priority Reserved Data
Page
PDU
Format
PDU
Specific
Source
Address
1 Bit 2 Bits 3 Bits 1 Bit 1 Bit 8 Bits 8 Bits 8 Bits
1 Byte 1 Byte 1 Byte 1 Byte
7.0 TARSIMU SPECIFIC MESSAGES
The TARS-IMU transmits three messages every 10 ms (100 Hz).
7.1 PGN 61481 (0xF029) Pitch and Roll Angles (°) Broadcast
Data
Table 8. PGN 61481 Details
Pitch Angle Roll Angle Status Latency
1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte
0x00 0x00 0x7D 0x00 0x00 0x7D 0x00 0x0A
BL BM BH BL BM BH
uint32 = B
H
*2^16 + B
M
*2^8 + B
L
Angle (°) = (uint32 - 8192000) / 32768
7.2 PGN 61481 Status
The status byte is comprised of compensation status and
MEMS status for each value.
Table 9. PGN 61481 Status
Pitch Roll
Comp Status Comp Status
00b 00b 00b 00b
All status definitions are defined as:
00b = Fully Functional
01b = Degraded
10b = Error
11b = Not Available
e.g., 0xCF029E2, 0x00, 0x00, 0x7D, 0x00, 0x00, 0x7D, 0x00, 0x05
Transmit 0° on both pitch and roll with priority 3, fully
functional MEMS and compensation with 5 ms latency from
address 0xE2.
7.3 PGN 61482 (0xF02A) Gyro (°/s) Broadcast Data
Table 10. PGN 61482 Details
Pitch Rate Roll Rate Yaw Rate Status Latency
1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte 1 Byte
0x00 0x7D 0x00 0x7D 0x00 0x7D 0x00 0x0A
BL BH BL BH BL BH
uint16 = B
H
*2^8 + B
L
Rotation Rate (°/s) = (uint16 - 32000) / 128