Omron C200HW-CORT21-V1, Operation Manual

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Transmitting a user defined CAN message
Section 5-7
79
5-7 Transmitting a user defined CAN message
Control code #0003
The C200HW-CORT21-V1 allows transmission of arbitrary CAN messages
with the IOWR instruction. If it is not required that the CANopen protocol is
active at the same time, IR n.00 can be set to ‘0’.
This function is only for advanced users that have knowledge of the CAN
protocol. The C200HW-CORT21-V1 does not check the validity of the CAN
message.
The frame of a CAN message is shown in the picture below.
* Identifier (11 bits) * Data length (DLC) Data byte 1 Data byte 8 *
* Frame control bits, not important for this function
To transmit a CAN message, it is necessary to specify the identifier of the
frame, the data length
(number of data bytes)
and the actual data (up to a
maximum of 8 bytes). The figure below shows the IOWR message structure.
IOWR message structure
word n
Identifier [hex] range: 0000h ~ 07FFh
word n+1 Data length range: 0000 ~ 0008
word n+2 Data byte 2 Data byte 1
word n+3 Data byte 4 Data byte 3
word n+4 Data byte 6 Data byte 5
word n+5 Data byte 8 Data byte 7
Note
Transmission time-out
The C200HW-CORT21-V1 ignores bits 11 to 15 of word n.
If no other node is connected to the network, or if the CAN interface of the
Unit is in error, the C200HW-CORT21-V1 will not be able to transmit the
message. After a time-out of 50 ms, the error code 0431 is added to the error
log. If more IOWR transmission requests are issued during this time-out
period, the transmission of these messages will be aborted. An error code
0431 is added to the error log for each message that was aborted.
!
Caution