14
Changing the CAN Baud Rate & Shutdown Delay
The device comes preconfigured with a default CAN baud rate of 1Mbps, and a shutdown
delay of 200ms. These values can be changed using any CAN bus interface device capable
of transmitting a message onto the CAN bus. The following procedure is used to change the
CAN baud rate and shutdown delay on the Master Relay:
1.
Configure the CAN interface device to transmit a single message on address 0x789
with the following format:
Table 12: Example CAN baud rate & shutdown delay configuration message
Byte
0
1
2
3
4
5
6
7
Data
0x04 0x56
BAUD
RATE
BAUD
RATE
SHUT
DELAY
SHUT
DELAY
0x04 0x56
Example*
0x04 0x56 0x01 0x01 0x0A 0x0A 0x04 0x56
* shows the correct message format to set the baud rate to 500Kbps and the shutdown delay to 1 second.
Where ‘
BAUD RATE
’ is
from the table below
and ‘SHUT DELAY’ is the delay in
tenths of a second that the power is kept on after a shutdown event (in hex).
Table 13: List of baud rate enumerations
Baud Rate Value
‘BAUD RATE’
1Mbps (Default)
0x00
500Kbps
0x01
250Kbps
0x02
2.
Press and hold the external kill switch while sending the above message.
3.
The Master Relay will send a response message on the base CAN address. See
Table 14 for a list of responses.
Table 14: Responses for CAN baud rate & shutdown delay configuration
0
1
2
3
4
5
6
7
Successful
0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
Values do not match
0x11 0x11 0x11 0x11 0x11 0x11 0x11 0x11
Frame check error
0x22 0x22 0x22 0x22 0x22 0x22 0x22 0x22
Invalid baud rate
0x33 0x33 0x33 0x33 0x33 0x33 0x33 0x33
4.
After a successful response the Master Relay will need to be restarted (by removing
the power) before the new CAN baud rate is implemented. The shutdown delay is
effective immediately.
