Omron CJ2 CPU - REV 10-2010 User Manual page 460

11 Programming Devices and Communications
Parameter
Communications Settings
Mode
Serial PLC Link Unit Number
Link Method (Data Refresh Method)
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 updated in both the Polling Unit and the Polled
Units. The only exceptions are the data for Polled Units that are not present in the network and the
data for any PTs that are connected. These data areas are unstable in all nodes.
Example: Complete Link Method, Highest Unit Number: 3
In the following diagram, Polled Unit 2 is a Unit not present in the network or a PT, so the words allo-
cated for Polled Unit 2 are unstable in all nodes.
Polling Unit
Send words
Polled Unit 0
Polled Unit 1
Unstable
Polled Unit 3
Not used.
Not used.
Not used.
Not used.
Polling Unit Link Method
The data for all the Polled Units in the Serial PLC Links are updated in the Polling Unit only, and
each Polled Unit updates the data of the Polling Unit only. The advantage of the Polling Unit link
method is that the addresses allocated for the local Polled Unit data are the same in each Polled
Unit, allowing data to be accessed using common ladder programming. The data for polled units that
are not present in the network and the data for any PTs that are connected are unstable in all nodes.
11-24
Set the communications settings to match those of the con-
nected PLC.
If the connected PLC is set to 115,200 bps, select the Cus-
tom Option and set the baud rate to 115,200. It does not
matter what is selected for the Parameter setting.
Select PC Link Polled Unit.
Set the unit number (0 to 7).
Polled Unit 1
Polled Unit 0
Polling Unit
Polling Unit
Send words Polled Unit 0
Send words
Polled Unit 1
Unstable
Unstable
Polled Unit 3
Polled Unit 3
Not used. Not used.
Not used. Not used.
Not used. Not used.
Not used. Not used.
Setting
Polled Unit 3
Polling Unit
Polled Unit 0
Polled Unit 1
Unstable
Send words
Not used.
Not used.
Not used.
Not used.
CJ2 CPU Unit Software User's Manual