Communication
FPΣ User's Manual
232
8.7.3 Setting the Highest Station Number for a PLC Link
Station numbers should be set sequentially and consecutively, starting from 1, with no breaks
between them. If there is a missing station number, or if there is a station for which the power
supply has not been turned on, the response time for the PLC link (the link transmission cycle
time) will be longer (see page
239).
If there are fewer than 16 stations linked, set the highest station number to reduce the link
transmission cycle time. (The default value is 16.) Set the same value for all PLCs in the link.
The highest station number is set using system register no. 47 for PLC link 0 or system
register no. 57 for PLC link 1.
Sample settings
Total number of stations 2 4 n
Station number 1 2 1 2 3 4 n
Highest station number
1)
2 2 4 4 4 4 N
1)
Same setting for each station
8.7.4 PLC Link 0 and 1 Allocation Setting
The default setting of system register 46 (PLC Link 0 and 1 allocation setting) is "Normal".
This means that the unit which is closest to the CPU uses PLC link 0 and the unit which is
further away uses PLC link 1. To reverse this behavior, select "Reverse". In the example
below, selecting "Reverse" for the PLCs in PLC link 1 (B) has the advantage that the user
does not have to make any address conversions between these PLCs and the MCU. Instead,
the same numbers may be used for all PLCs in the link.
MCUMCU
B
A
FP2
1
In the default setting ("Normal"), the first half of the link relays and link registers is used
(WL0-WL63, LD0-LD127).
2
In the default setting ("Normal"), the second half of the link relays and link registers is
used (WL64-WL127, LD 128-LD225).
A
PLC link 0
B
PLC link 1 - Set system register 46 to "Reverse" in the PLCs of PLC link 1.
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