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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
5-2-6 Synchronous Output Refreshing
z Slave Terminal Operation
The following describes the operation of synchronous output refreshing of an EtherCAT Slave Ter-
minal connected to the built-in EtherCAT port.
• All Digital Output Units and Analog Output Units that operate with synchronous output refreshing
in the Slave Terminal refresh their outputs at the same time at a fixed interval based on Sync0.
(Refer to (a) in the figure below.)
*1
• The Communication Coupler Unit refreshes the output values at I/O refreshing. Refer to (b) in the
figure below.)
• The interval of I/O refreshing varies with the processing conditions of the Communications Cou-
pler Unit or the host communications master. (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 Sync0, the timing to refresh outputs and the maximum NX bus I/O refresh cycle of the Slave
Terminals are automatically calculated by the Sysmac Studio according to the output refresh cycle
of the NX Units in the Slave Terminals when the Slave Terminals are configured 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.)
*1. If multiple Slave Terminals are present on the same EtherCAT network, refer to the NX-series EtherCAT
Coupler Unit User’s Manual (Cat. No. W519-E1-05 or later) for the range of available Slave Terminals that
operate at the same timing.
Offset between synchronization timing and timing to refresh outputs
This time is automatically calculated by the Sysmac Studio.
(c) Interval of I/O refreshing
is not constant.
I/O refreshing synchronization
The longest DA conversion time
is within one cycle.
(d) Interval of synchronization timing
is constant.
(b) The CPU Unit refreshes the output
values at I/O refreshing.
Timing to refresh
outputs
Synchronization
timing
Synchronization
timing
1234
Synchronization timing
ConstantConstant
1234
Output 1 Output 2
ON/OFF
response
time
DA conversion
time
12341234
Output 2
12341234
Output 1 Output 2
Digital Output Unit A
Digital Output Unit B
Analog Output Unit A
Analog Output Unit B
Not constant.
(e) ConstantConstantConstant
Output 1
Wait time
Wait time
I/O refreshing
of the NX bus
(a) All Outputs Units that support synchronous
output refreshing read their outputs simultaneously.
(f) Set outputs
Input refreshing
Output refreshing
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