Omron CP1L - 12-2007, Operation Manual

Page: 386 / 673

353
Serial Communications
Section 6-3
Specifications
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.
Item Specifications
Applicable serial
ports Serial port 1 or 2. Both ports cannot be used for PLC Links at
the same time. If both ports are set for PLC Links (either as
polling node or polled node), a PLC Setup setting error (non-
fatal error) will occur and the PLC Setup Setting Error Flag
(A402.10) will turn ON.
Connection method RS-422A/485 or RS-232C connection via RS-422A/485 or
RS-232C Option Board.
Allocated data area Serial PLC Link Words:
CIO 3100 to CIO 3199 (Up to 10 words can be allocated for
each CPU Unit.)
Number of Units 9 Units max., comprising 1 Polling Unit and 8 Polled Units (A
PT can be placed on the same network in an 1:N NT Link, but
it must be counted as one of the 8 Polled Units.)
Link methods (data
refresh methods) Complete link method or Polling Unit link method
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)