Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual page 1026

Serial Communications Instructions
Flags
Precautions
986
Name Label
Error Flag ER
TXD(236) can be used only for the CPU Unit's RS-232C port or one of the
Serial Communications Board's serial ports. In addition, the port must be set
to no-protocol mode.
The following send-message frame format can be set in the PLC Setup (for
the CPU Unit's RS-232C port) or the allocated DM Setup Area (for the Serial
Communications Board's ports).
• Start code: None or 00 to FF hex.
• End code: None, CR+LF, or 00 to FF hex.
The data will be sent with any start and/or end codes specified in the PLC
Setup or the allocated DM Setup Area. If start and end codes are specified,
the codes will be added to the send data (N). In this case, the maximum num-
ber of bytes that can be specified for N is 256 bytes.
Data can be sent only when the port's Send Ready Flag is ON. (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.)
Data is sent in the order specified in C.
Nothing will be sent if 0 is specified for N.
If RS signal control is specified in C, bit 15 of S will be used as the RS signal.
If ER signal control is specified in C, bit 15 of S will be used as the ER signal.
If RS and ER signal control is specified in C, bit 15 of S will be used as the RS
signal and bit 14 of S will be used as the ER signal.
If 1, 2, or 3 hex is specified for RS and ER signal control in C, TXD(236) will be
executed regardless of the status of the Send Ready Flag (A39205, A35605,
or A35613 depending on the port being used).
If the TXD(236) instruction is executed for a Board that does not support no-
protocol mode (a Serial Communications Board without a version number),
Operation
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.)
ON if a TXD(236) was executed for a serial port on a
Serial Communications Board that was being restarted.
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