809
Serial Communications Instructions Section 3-23
Flags
Precautions The data in the send area specified with S is actually sent using the symbol
read option, R( ), in a send message.
Data is actually received to the receive area specified by R using the symbol
write option, W( ), in a receive message.
Refer to the CX-Protocol Operation Manual (W344) for procedures for desig-
nating symbols R( ) and W( ).
PMCR(260) can be executed for a serial communications port on a Serial
Communications Unit. Up to 2 Serial Communications Units can be mounted
as CJ-series Expansion Units. The unit address of the communications part-
ner must be set in bits 0 to 7 of C1 to specify which Unit is to be used and the
serial port number must be set in bits 8 to 11. Unit addresses are specified as
shown in the following table.
The corresponding Protocol Macro Execution Flag will turn ON at the start of
PMCR(260) execution. It will turn OFF after the communications sequence
has been completed and data has been written to the specified receive area.
A N.C. input for the corresponding Protocol Macro Execution Flag should be
used as part of the execution condition whenever executing PMCR(260) to be
sure that only one communications sequence is being executed at the same
time for the same physical port. An example is shown below.
R m
S
n
CPU Unit
n
to
to
External
device
CJ-series Serial
Communications Unit
Port
Communications
sequence No.
CJ Unit Adapter
Name Label Operation
Error Flag ER ON if the Communications Port Enabled Flag is OFF for
the specified logical port when PMCR(260) is executed.
ON if C1 is not within the specified ranges. (Error flag will
not turn ON if the C2 data is outside the specified ranges.
The end code will be stored in the Communications Port
Completion Code (A203 to A210) of the auxiliary area.)
ON if the number of words of S or R exceeds 249 (when
words are specified).
OFF in all other cases.
Unit/Board Unit address
Serial Communications Unit Unit number + 10 hex
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