Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual page 1070

Network Instructions
Host computer
Host Link
FINS
command
Host Link header
1030
• Sending to a PLC operating as a Host Link Slave
When a CMND(490), SEND(090), or RECV(098) instruction is executed to
a serial port that supports the serial gateway function, the serial gateway
function can send any FINS command or send/receive data.
Communications from a Host Computer (Host Link)
It is possible to send FINS commands from a host computer to the PLC to
which it is connected as well as other devices in the network (CPU Units, Spe-
cial I/O Units, computers, etc.). In this case, the necessary Host Link header
and terminator must be attached to the FINS command when it is sent.
Host Link FCS
and terminator
FINS command
CMND
PLC
Modbus RTU
Serial cable
Modbus-RTU Slave device
CMND
PLC
Host link FINS
Serial cable
PLC
Host Link Slave
Section 3-25