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Network Instructions Section 3-24
Transmission from a Host
Computer Connected
through Host Link
When the Serial Communications Option Board mounted on a CP-series CPU
Unit or a CJ-series Serial Communications Unit is in Host Link and connected
one-to-one with a host computer, RECV(098) can be executed to receive data
from the host computer the next time that the PLC has the right to transmit
commands. It is also possible to receive data from other host computers con-
nected to other PLCs elsewhere in the network.
If RECV(098) is executed for the Serial Communications Option Board
mounted on a CP-series CPU Unit or a CJ-series Serial Communications
Unit, a command is sent from the serial port to the host computer. The com-
mand is a FINS message enclosed between a host link header and termina-
tor. 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 com-
mand (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 (Serial Communications Option Board on CPU Unit), or
unit number + 10 hexadecimal (CJ-series Serial Communications Unit).
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 con-
nected as a host link Slave to a Serial Communications Unit. In this case, the
source node address must be set to the host link unit number + 1.
PLC PLC
Data
Network
CP1H
Host computer
Host Link
Data
Serial port
Serial cable
PLC
Host Link Slave
Set the source node address to the host
link unit number + 1 = S+1.
Host link unit number: S
RECV
CP1H
Data
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