Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 1017

Serial Communications Instructions
Precautions
978
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 Board (CS Series only) or Serial Communications Unit. Up
to 16 Serial Communications Units can be mounted to the CPU Rack and
Expansion I/O Racks. The Unit address of the communications partner must
be set in bits 0 to 7 of C1 to specify which Unit/Board 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.
Unit/Board
Serial Communications Board
(CS Series only)
Serial Communications Unit
Serial Communications Units
Unit address
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.
Execution
condition
SEND(090), RECV(098), and CMND(490) also use the logical ports 0 to 7 to
execution communications sequences through Serial Communications Unit
and Boards (internally using FINS commands). PMCR(260) cannot be exe-
cuted for a logical port that is already being used by SEND(090), RECV(098),
CMND(490)or PMCR(260). To prevent more than one communications
sequence from being executed for the same logical port, the corresponding
Communications Port Enable Flag (A20200 to A20207) should be used as a
N.O. input in the execution condition for PMCR(260), as shown in the above
diagram.
E1 hex
Unit number + 10 hex
Serial Communications Board
(CS Series only)
E1 hex (CS Series only)
Unit No. + 10 hex
Protocol Macro Communications Port
Execution Flag Enabled Flag
Section 3-24
Unit address
PMCR(260)