822
Serial Communications Instructions Section 3-23
Flags
Precautions RXD(235) can be used only for serial ports on Serial Communications Option
Boards mounted to the CPU Unit. In addition, the port must be set to no-proto-
col mode.
The following receive message frame format can be set in the PLC Setup.
• Start code: None or 00 to FF hex
1 2 3 4 5 6 0...
1 2 3 4 5 6 0...
1 2 3 4 5 6 0...
1 2 3 4 5 6 0...
1 2 3 4 5 6 0...
1 2 3 4 5 6 0...
1
3
5
2
4
6
1
3
5
2
4
6
1
2
3
4
5
6
LFCR
Bytes
Receive bytes: Specified
in the PLC Setup
Receive bytes after ST:
Specified in the PLC Setup
Receive bytes before
ED: 256 max.
Receive bytes between
ST and ED: 256 max.
Receive bytes before
CR+LF: 256 max.
Receive bytes between
ST and CR+LF: 256 max.
When receiving the most signifi-
cant bytes first is specified (0):
Most signifi-
cant bytes
Least signif-
icant bytes
When receiving the least signifi-
cant bytes first is specified (1):
Most signifi-
cant bytes
Least signif-
icant bytes
N bytes
stored in the
specified or-
der.
Max: 256 bytes
Received
Start and CR+LF End Code
CR+LF End Code
Start and End Code
Only End Code
Only Start Code
No Start or End Code
Serial port on Serial Communications Option Board
···
Name Label Operation
Error Flag ER ON if no-protocol mode is not set in the PLC Setup.
ON if the value of C is not within range.
ON if the value for N is not between 0000 and 0100 hex.
OFF in all other cases.
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