Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 1072

Network Instructions
Execution Communications
condition Port Enabled Flag
Reset B
Local Node
Active Flag
Communications
Port Enabled Flag
Communications
Port Error Flag
Execution Communications
condition Port Enabled Flag
Reset D
Automatic Allocation of
Communications Ports
The following diagram shows an example of exclusive control.
Destination
Node Active
Flag
Same as above.
■ Overview
The following instructions all use one communications port (logical port)
between ports 0 to 7.
• Network Communications Instructions: SEND(090), RECV(098), and
CMND(490)
• Serial Communications Instructions: PMCR(260), TXDU(256), and
RXDU(255)
In this section, all of the above instructions are referred to as Communications
Instructions.
Each communications port can be used by only one instruction at a time. The
following steps were previously necessary to use the communications ports.
• When programming, it was necessary to keep track of the communica-
tions ports that were being used to designate them in operands.
• In the ladder program, it was necessary to confirm the availability of com-
munications ports before using them.
Bit A remains ON while the communications
instruction is being executed.
KEEP A
Copies the operand and control data to the
Creates op-
desired data area.
erand or
control data
with @MOV
or @XFER.
Executes the communications instruction.
@SEND,
@RECEIVE,
@CMND
Writes the reset input. (Reset B is turned
ON when the communications instruction
DIFU B
is completed.)
For Transmission Error Flag display
(Good if data is retransmitted.)
Exclusive control to prevent simulta-
neous execution:
KEEP C
Exclusive control prevents another
communications instruction from being
executed until the instruction above is
completed.
Section 3-25
1033