5 I/O Refreshing
5 - 16
NX-series Analog I/O Units User’s Manual for Analog Input Units and Analog Output Units (W522)
The I/O refreshing method described below. Among Slave Terminals, this refreshing method is
supported only by EtherCAT Slave Terminals.
• The timing to refresh outputs is synchronized on a fixed interval between more than one NX Unit con-
nected to a CPU Unit.
• The timing to refresh outputs is synchronized on a fixed interval between more than one NX Unit on
more than one Slave Terminal.
This method is used when the problem such as input timing jitter or offset of timing to refresh outputs
between more than one NX Unit happens.
z CPU Unit Operation
The following describes the operation of synchronous output refreshing between the NX-series
NX1P2 CPU Unit and the NX Units.
• All Digital Output Units and Analog Output Units that are connected to the CPU Units and operate
with synchronous output refreshing refresh their outputs at the same time at a fixed interval based
on the synchronization timing. (Refer to (a) in the figure below.)
• The CPU Unit refreshes the output values at I/O refreshing. (Refer to (b) in the figure below.)
• The Analog Output Units perform DA conversion with the output set values that are refreshed
once for each refresh cycle of the NX bus in order to output the DA converted values of all outputs
for which the used channels are set to enable at the time to refresh outputs.
• The interval of I/O refreshing varies with the processing conditions of the CPU Unit. (Refer to (c) in
the figure below.) The timing to refresh outputs will be at a fixed interval. (Refer to (d) and (e) in
the figure below.)
• The timing of refreshing outputs, the synchronization timing, and the maximum NX bus I/O refresh
cycle are automatically calculated by the Sysmac Studio according to the output refresh cycles of
the NX Units on the CPU Unit when a Unit configuration in the CPU Unit is created and set up.
• The ON/OFF response time is needed from the timing to refresh outputs until setting the output
status of external terminals on the NX Units. (Refer to (f) in the figure below.)
5-2-6 Synchronous Output Refreshing
Description of Operation
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