Omron CJ - REFERENCE MANUAL 02-2010 Reference Manual page 956

3. Instructions
Receiving Data from a Host Link Slave PLC Connected by Serial Gateway
The serial gateway function can be used to receive
data from a PLC connected as a host link Slave to a
Serial Communications Board or Unit. In this case,
the source node address must be set to the host link
unit number + 1.
Hint
Transmission through Host Link
If RECV(098) is executed for the serial port of the CPU Unit, a Serial Communications Board (CS
Series only), or Serial Communications Unit, a command is sent from the serial port to the host
computer. The command is a FINS message enclosed between a host link header and terminator. The
FINS command is a MEMORY AREA READ command (command code 0101) and the host link header
code is 0F hexadecimal.
A program must be created in the host computer to process the send command (the FINS command
enclosed in the host link header and terminator).
If the destination serial port is in the local PLC, set the network address to 00 (local network) in C+1, set
the node address to 00 (local PLC) in C+2, and set the unit address to 00 (CPU Unit), E1 (Inner Board,
CS Series only), or unit number + 10 hexadecimal (Serial Port Unit).
Precaution
• Only one network instruction may be executed for a communications port at one time. To ensure that
RECV(098) is not executed while a port is busy, program the port's Communications Port Enabled
Flag (A202.00 to A202.07) as a normally open condition.
• Refer to Automatically Allocating Communications Ports (i.e., Internal Logical Ports) on page 1115 for
details on using automatic allocation of the communications port number (logical port).
• Communications port numbers 00 to 07 are shared by the network instructions and PMCR(260), so
RECV(098) cannot be executed simultaneously with PMCR(260) if the instructions are using the
same port number.
• Noise and other factors can cause the transmission or response to be corrupted or lost, so we
recommend setting the number of retries to a non-zero value which will cause RECV(098) to be
executed again if the response is not received within the response monitoring time.
920
RECV
PLC
Set the source node address to the host
link unit number + 1 = S+1.
Data
Serial cable
CS/CJ/NSJ Series Instructions Reference Manual (W474)
PLC
Host Link Slave
Host link unit number: S