Omron NX-ECC201 User Manual page 223

Example of I/O Refreshing Method Operation
An example of operation for each I/O refreshing method is provided in the following figure. This exam-
ple contains NX Units that operate with synchronous I/O refreshing in DC Mode and other NX Units that
operate with Free-Run refreshing.
PLC Function
Module
EtherCAT Master
Function Module
EtherCAT
communications path
Synced slave #1
EtherCAT Slave
Terminal #2
EtherCAT
Coupler Unit
Synchronized NX
Unit (No. 1)
Synchronized
NX Unit (No. 2)
Synchronized
NX Unit (No. 3)
EtherCAT Slave
Terminal #3
EtherCAT Coupler
Unit
Synchronized NX
Unit (No. 1)
Synchronized NX
Unit (No. 2)
Synchronized NX
Unit (No. 3)
Free-run NX Unit
(No. 4)
Operation is as follows in Free-Run Mode:
• The NX bus refresh cycle is not synchronized with the primary period or process data communica-
tions cycle. The NX bus operates on its own cycle.
• The refresh cycle of the NX bus and the I/O refresh cycles of the NX Units are asynchronous.
NX-series EtherCAT Coupler Unit User's Manual (W519)
Primary periodic task Primary periodic task
Primary period
(example: 500 μs)
Process data communica- Process data communica-
tions cycle (example: 500 μs)
tions cycle (example: 500 μs)
EtherCAT transmission EtherCAT transmission
time time
Period of Sync0
(example: 500 μs)
(Sync0) (Sync0)
Refresh cycle of the NX Refresh cycle of the NX
bus (example: 500 μs)
Input data
Output data
Output data
transmission
transmission
transmission
time for
time for
time for
EtherCAT
EtherCAT
EtherCAT
Coupler Unit
Coupler Unit
Coupler Unit
ON/OFF response time
ch1 ch2 ch1 ch2 ch1
DA conversion
time for each Unit All Units with synchronous output refreshing
refresh their outputs simultaneously (B)
ON/OFF response time
ch1 ch2 ch1 ch2 ch1
DA conversion time for
each Unit
Processing of free-run NX Unit (No. 4)
Primary periodic task
Primary period
Primary period
(example: 500 μs) (example: 500 μs)
Process data communica-
tions cycle (example: 500 μs)
EtherCAT transmission
time
Period of Sync0 Period of Sync0
(example: 500 μs)
(example: 500 μs)
(Sync0)
Refresh cycle of the NX
bus (example: 500 μs) bus (example: 500 μs)
Input data transmission
time for EtherCAT Output data transmission time
for EtherCAT Coupler Unit
Coupler Unit
All Units with synchronous input refreshing
read their inputs simultaneously (A).
ch2 ch1 ch2 ch1 ch2
ch2 ch1 ch2 ch1 ch2
Processing of free-run NX Unit (No. 4)
(D)
(C)
10 I/O Refreshing
ON/OFF response
time + Input filter time
ch1 ch2
AD conversion time
for each Unit
ON/OFF response
time + Input filter time
ch1 ch2
AD conversion time
for each Unit
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