FPΣ User's Manual
8.1 Communication Modes
157
8.1.5 PLC Link
PLC Link is an economic way of linking PLCs using a twisted-pair cable and the MEWNET
protocol. Data is shared with all PLCs by means of dedicated internal relays called link relays
(L) and data registers called link registers (LD). The statuses of the link relays and link
registers of one PLC are automatically fed back to the other PLCs on the same network. The
link relays and link registers of the PLCs contain areas for sending and areas for receiving
data. Station numbers and link areas are allocated using the system registers.
EXAMPLE
Link relay L0 for station #1 turns to TRUE. The status change is fed back to the
programs of the other stations, and Y0 of the other stations is set to TRUE. A
constant of 100 is written to link register LD0 of station #1. The contents of LD0 in the
other stations are also changed to a constant of 100.
R0
L0 L0
Y0
L0
Y0 Y0
L0
LD 0 100
100LD 0
RS485
#1 #4#2 #3
#1
#4#2 #3
100LD 0 100LD 0
PLC Link connection between four FPΣ units
# Station number of PLC LD Link register
REFERENCE
For detailed information on the PLC Link communication mode, see "PLC Link"
on page
223.
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