Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 1025

Serial Communications Instructions
1 2
3 4
5 6
Flags
986
The following diagram shows the order in which data is sent and the contents
of the send frame for various start and end code settings.
N bytes of data is sent in the following order when
sending the most significant bytes first is specified:
1, 2, 3, 4, 5, 6
No Start or End Code
Only Start Code
Only End Code
Start and End Code
CR+LF End Code
Start and CR+LF End Code
RS-232C port on CPU Unit
Name Label
Error Flag ER
Data
Data
Data
Data
Data
CR LF
Data
Data sent.
ON if the CPU Unit's RS-232C port is specified as the
send port, but no-protocol mode is not set in the PLC
Setup.
ON if one of the Serial Communication Board's serial
ports is specified as the send port, but no-protocol mode
is not set in the port's allocated DM Setup Area.
ON if the value of C is not within range.
ON if the value for N is not between 0000 and 0100 hex.
ON if a send is attempted when the Send Ready Flag is
OFF. (The Send Ready Flag is A39205 for the CPU Unit's
RS-232C port, A35605 for Serial Communications Board
port 1, or A35613 for Serial Communications Board port
2.)
ON (ER Flag in interrupt tasks) if a TXD(236) or
RXD(235) instruction is being executed for the Serial
Communications Board in the cyclic task, the cyclic task
is interrupted, and another TXD(236) or RXD(235)
instruction is executed for the Serial Communications
Board in the interrupt task. (See note.)
Note The Error (ER) Flag will turn ON immediately after
another TXD(236) or RXD(235) instruction in the
interrupt task.
OFF in all other cases.
Section 3-24
N send bytes: 256 max.
Send bytes after ST:
256 max.
Send bytes before ED:
256 max.
Send bytes between
ST and ED: 256 max.
Send bytes before
CR+LF: 256 max.
Send bytes between ST
and CR+LF: 256 max.
Operation