NAiS FP2, Technical Manual

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5-11
Setting the largest unit number for a PC(PLC) link
The largest unit number can be set using system register no. 47 (using system register no. 57 for
PC(PLC) link 1).
[Sample setting]
No. of units linked Setting contents
2 1st unit: Unit no. 1 is set
2nd unit: Unit no. 2 is set
A largest unit no. of 2 is set for each.
4 1st unit: Unit no. 1 is set
2nd unit: Unit no. 2 is set
3rd unit: Unit no. 3 is set
4th unit: Unit no. 4 is set
A largest unit no. of 4 is set for each.
n Nth unit: Unit no. n is set
A largest unit no. of n is set for each.
Note:
•
Unit numbers should be set seq uentially and consecutively, starting from 1, with no breaks between
them. If there is a missing unit number, the transmission time will be longer.
•
If fewer than 16 units are linked , the transmission time can be shortened by setting the largest unit
number in system register no. 47 (in system register no. 57 for PC(PLC) link 1).
•
For all PLCs which are linked, t he same value should be set for the largest unit number.
•
If there are fewer than 16 units linked and the largest unit number has not been set (default=16), or the
largest unit number has been set but the unit number settings are not consecutive, or the unit number
settings are consecutive but there is a unit for which the power supply has not been turned on, the
response time for the PLC link (the link transmission cycle) will be longer.
Reference: <5.5 PC(PLC) Link Response Time>.
Setting PC(PLC) link switching flag
PC(PLC) link switching flag can be set using system register no. 46.
If it is set to 0 (default value), the first half of the link relay (WL0 to WL63) and register (LD0 to LD127) is
used for the first PC(PLC) link unit (PC link W0 or PC link W), and the second half of the link relay (WL64
to WL127) and register (LD128 to LD255) is used for the second PC(PLC) link unit. However, if it is set
to 1, the second half of the link relay and register is used for the first PC(PLC) link unit (PC link W0 or PC
link W).