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5 I/O Refreshing
NX-series Digital I/O Unit User’s Manual (W521)
5-2 I/O Refreshing Methods
5
5-2-1 Types of I/O Refreshing Methods
5-2 I/O Refreshing Methods
This section describes I/O refreshing methods for the NX Units.
The I/O refreshing methods that you can use between the Communications Coupler Unit and the NX
Units are determined by the Communications Coupler Unit that is used.
When an EtherCAT Coupler Unit is connected to the built-in EtherCAT port on the NJ-series CPU Unit,
the I/O refreshing methods that you can use between the EtherCAT Coupler Unit and the NX Units are
as follows.
Since the EtherCAT Coupler Unit can execute all I/O refreshing methods at the same time, you can use NX Units
with different I/O refreshing methods together in the EtherCAT Slave Terminal.
5-2-1 Types of I/O Refreshing Methods
I/O refreshing method name Outline of operation
Free-Run refreshing With this I/O refreshing method, the refresh cycle of the NX bus and the I/O
refresh cycles of the NX Units are asynchronous.
Synchronous I/O refreshing With this I/O refreshing method, the timing to read inputs or to refresh out-
puts is synchronous on a fixed interval between more than one NX Unit on
more than one Slave Terminal.
Time stamp refreshing With this I/O refreshing method, the NX Units record the DC times when
inputs change or perform outputs at specified DC times. These times are
asynchronous to the NX bus refresh cycles.
Data exchange between the NX Units and EtherCAT Coupler Unit are per-
formed cyclically on the NX bus refresh cycles.
Input refreshing with input
changed time
With this I/O refreshing method, the Input Units record the DC times when
inputs changed.
Output refreshing with
specified time stamp
With this I/O refreshing method, the Output Units refresh outputs at specified
DC times.
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