ECM NH3CAN, Instruction Manual, Page: 10 / 35

10
4.0 Getting Information from the NH
3
CAN Module
As soon as power is attached to the NH
3
CAN module, it will perform a POWER ON/RESET
sequence during which the bi-color LED will display a 2 second GREEN/BOTH/RED pattern.
After the POWER ON/RESET sequence is finished, the LED will flash green at 10Hz until the
NH
3
sensor has reached its operating temperature. This may take up to 30 seconds. Once the
sensor is ready and the NH
3
data is valid, the bi-color LED will display GREEN continuously.
If there is an error, the LED color will change to RED and flash a number of times every 2
seconds indicating an error code. This error code will also be transmitted on the CAN bus. See
ECM Error codes in Appendix A.
Approximately 5 seconds after power is applied, the unit will start broadcasting CAN messages
at a CAN baud rate of 500kbps. All messages are related to the Node ID (NID) of the particular
module. As shipped, the NID is pre-assigned and is written on a label above the LED. The NID
can be changed using the supplied configuration software.
4.1
CANopen Message Types
i) HEARTBEAT (Broadcast rate = 0.5sec, DLC=1)
CAN id byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7
0x700+NID value
value = NMT STATE (see Appendix C)
ii) ERROR (Broadcast rate = 0.250sec, DLC=6)
CAN id byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7
0x80+NID 0x00 0xFF 0x81 lo byte 0x00 count
lo byte = ECM Error Code (0x01 = Sensor Warm-up, 0x00 = Data valid, see Appendix A)
count = Sensor Warm-up countdown in seconds (active during ECM Error Code 0x01)