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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
5-2-5 Synchronous Input Refreshing
With this I/O refreshing method, the timing to read inputs is synchronized on a fixed interval between
more than one NX Unit on the Slave Terminal.
This method is used when the problem such as input timing jitter or offset of timing to read inputs
between more than one NX Unit happens.
• This method is used when you connect the NX Units that support synchronous I/O refreshing to the
EtherCAT Coupler Unit that is connected to the built-in EtherCAT port on the NJ-series CPU Unit.
• All Digital Input Units and Analog Input Units that operate with synchronous input refreshing in the
Slave Terminal read their inputs at the same time at a fixed interval bases on Sync0. (Refer to (a) in
the figure below.)
• The Communications Coupler Unit reads the input values that are latched at the time to read inputs
at immediate I/O refreshing. (Refer to (b) in the figure below.)
• The interval of I/O refreshing varies with the processing conditions of the Communications Coupler
Unit or the host communications master. (Refer to (c) in the figure below.) The timing to read inputs
will be at a fixed interval. (Refer to (d) in the figure below.)
• The Sync0, the timing to read inputs and the maximum NX bus I/O refresh cycle of the Slave Termi-
nals are automatically calculated by the Sysmac Studio according to the input refresh cycle of the NX
Units in the Slave Terminals when the Slave Terminals are configured and set up.
• In order to read input values correctly, you must determine the inputs before the total of the ON/OFF
response time and input filter time from the timing to read inputs for each NX Unit. (Refer to (e) in the
figure below.)
5-2-5 Synchronous Input Refreshing
Description of Operation
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