1024
Serial Communications Instructions Section 3-24
Differences between CPU Units
If the PLC is turned OFF and then ON again after STUP(237) has been used
to change the communications parameters, the new parameters will be
retained or will revert to the previous parameters, depending on the CPU Unit.
Flags
Precautions Communications parameters consist of the protocol mode, baud rate, data
format (protocol macro transmission method and protocol macro maximum
communications data length), and other parameters. Refer to CS/CJ-series
Programmable Controllers Operation Manual (W339) or CS/CJ-series Serial
Communications Boards and Serial Communications Unit Operation Manual
(W336) for the serial port that is to be set for details.
Related Flags and Words The following flags can be used as required when executing STUP(237).
These flags are in the Auxiliary Area.
Examples When CIO 000000 turns ON in the following example, the communications
parameters for serial port 1 of the Serial Communications Board (Inner Board)
are changes to the settings contained in the 10 words from D00100 to
D00109. In this example, the setting are changed the protocol mode to the
protocol macro mode.
CPU Unit Status of communications parameters
CS1-H, CJ1-H,
CJ1M, or CS1D
If the PLC is turned OFF and then ON again, the communications
parameters revert to the settings that existed before they were
changed with STUP(237).
CS1 If the PLC is turned OFF and then ON again, the communications
parameters set with STUP(237) are retained.
Name Label Operation
Error Flag ER ON if the values in C are not within range.
ON if STUP(237) is executed for a port whose Communi-
cations Parameter Changing Flag is already ON.
ON if STUP(237) is executed in an interrupt task.
OFF in all other cases.
Name Address Contents
Peripheral Port Parameters
Changing Flag
A61901 ON when the communications param-
eters are being changed for the periph-
eral port.
RS-232C Port Parameters
Changing Flag
A61902 ON when the communications param-
eters are being changed for the RS-
232C port.
Port Parameters Changing
Flags for ports 1 to 4 on
Serial Communications
Units 1 to 15.
A620 bit 01 to
bit 04
to A635 bit 01
to bit 04
ON when the communications param-
eters are being changed for a port on a
Serial Communications Unit.
Port Parameters Changing
Flags for ports 1 to 4 on the
Serial Communications
Board (CS Series only)
A63601 to
A63604
ON when the communications param-
eters are being changed for a port on
the Serial Communications Board.
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