Omron C200HW-CORT21-V1, Operation Manual

Page: 99 / 144

Receiving a user defined CAN message
Section 5-8
82
Message buffer
The received message(s) are first stored in a buffer in the Unit. Up to 15
messages can be stored. The last received message is always stored at the
top of the buffer and if there are already 15 messages stored, the oldest
message is shifted out of the buffer.
Receive Buffer
1
2 New message
3
4
5
6
7
8
9
10
11
12
13
14
15
Oldest message
New messages
During the I/O refresh, the messages stored since the last I/O refresh are
transferred to the PLC and IR n+3.03 is set to indicate that new user defined
CAN messages have been received. If no messages matching the identifier
filter have been received since the last I/O refresh, no data is transferred to
the PLC and IR n+3.03 is set to ‘0’.
The figure below shows the structure of the receive buffer. The
representation in the PLC memory after transferring the buffer to the PLC is
identical.
Receive buffer structure
word n Number of new messages
received since the last I/O
refresh [BCD] range: 0000 ~ 9999
word n+1 Identifier message 1 [hex] range: 0000h ~ 07FFh
word n+2 Data length range: 0000 ~ 0008
word n+3 Data byte 2 Data byte 1
word n+4
Data byte 4 Data byte 3
word n+5
Data byte 6 Data byte 5
word n+6
Data byte 8 Data byte 7
word n+7
Identifier message 2 [hex] range: 0000h ~ 07FFh
word n+8
Data length range: 0000 ~ 0008
word n+9 Data byte 2 Data byte 1
word n+10 Data byte 4 Data byte 3
word n+11 Data byte 6 Data byte 5
word n+12 Data byte 8 Data byte 7
word n+85
Identifier message 15 [hex] range: 0000 ~ 07FFh
word n+86 Data length range: 0000 ~ 0008
word n+87 Data byte 2 Data byte 1
word n+88 Data byte 4 Data byte 3
word n+89
Data byte 6 Data byte 5
word n+90
Data byte 8 Data byte 7
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