308
Serial Communications Section 6-3
System Configuration
Note 1. The CJ1W-CIF11 is not insulated and the total transmission distance is 50
meters max. If the total transmission distance is greater than 50 meters,
use the insulated NT-AL001 and do not use the CJ1W-CIF11. If only the
NT-AL001 is used, the total transmission distance can is 500 meters max.
2. Up to 8 Units, including the PT and Polled Units, can be connected to the
Polling Unit when a PT set for Serial PLC Link communications is on the
same network.
Data Refresh Methods
The following two methods can be used to refresh data.
• Complete link method
• Polling Unit link method
Complete Link Method The data from all nodes in the Serial PLC Links are reflected in both the Poll-
ing Unit and the Polled Units. (The only exceptions are the address allocated
to the connected PT’s unit number and the addresses of Polled Units that are
not present in the network. These data areas are undefined in all nodes.)
Example: Complete link method, highest unit number: 3.
In the following diagram, Polled Unit No. 2 is either a PT or is a Unit not
present in the network, so the area allocated for Polled Unit No. 2 is undefined
in all nodes.
Polling Unit Link Method The data for all the Polled Units in the Serial PLC Links are reflected in the
Polling Unit only, and each Polled Unit reflects the data of the Polling Unit only.
The advantage of the Polling Unit link method is that the address allocated for
the local Polled Unit data is the same in each Polled Unit, allowing data to be
RS-422/485
RS-232C
OR
CPU Unit
Polling Unit
CJ1W-CIF11
RS-422A
Converter
CPU Unit
Polled Unit No. 0
CPU Unit
Polled Unit No. 1
PT
Unit No. 2
CPU Unit
Polled Unit No. 3
Number of Polled Units: 8 max.
(See note 2.)
NS-AL002 when using
an NS-series PT
CPU Unit
Polling Unit
CPU Unit
Polled Unit No. 0
(See
note 1.)
Polling Unit Polled Unit No.0 Polled Unit No.1 Polled Unit No.3
Local area Polling Unit Polling Unit Polling Unit
Polled Unit
No.0
Local area
Polled Unit
No.0
Polled Unit
No.0
Polled Unit
No.1
Polled Unit
No.1
Local area
Polled Unit
No.1
Undefined Undefined Undefined Undefined
Polled Unit
No.3
Polled Unit
No.3
Polled Unit
No.3
Local area
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
(Not used)
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