Omron sysmac NX Series User Manual page 960

Appendices
Setting the I/O Refreshing Methods
For the Communication Control Unit, no setting operation is required, and the method is determined
according to the following table.
NX Unit that support only Free-Run refreshing
Free-Run refreshing
Selecting NX Units
The I/O refreshing methods that you can use depend on the model of the NX Unit. After you decide on
which I/O refreshing method to use, select the NX Units.
A-96
NX Unit that support both Free-Run refreshing and
Synchronous I/O refreshing
NX-series Safety Control Unit/Communication Control Unit User's Manual (Z395)
synchronous I/O refreshing