Panasonic FP0R User Manual page 120

7.6.2 Setting of Unit Numbers
By default, the unit number for the communication port is set to 1 in the system registers.
In a PC(PLC) link that connects multiple PLCs on the same transmission line, the unit number must be
set in order to identify the different PLCs.
The unit number is specified either by using the SYS1 instruction or the system register.
Note1) The priority order for unit number settings is as follows:
1. SYS1 instruction
2. System registers
Note2) Unit numbers should be set sequentially and consecutively, starting from 1, with no breaks
between them. If there is a missing unit number, the transmission time will be longer.
Note3) If fewer than 16 units are linked, the transmission time can be shortened by setting the largest
unit number in system register no. 47.
Unit numbers are the numbers to identify the different PLCs on the same network. The same number
must not be used for more than one PLC on the same network.
Note:
When using the PC(PLC) link with the RS232C, the number of units is 2.
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