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12 Communications Performance
NX-series EtherCAT Coupler Unit User’s Manual (W519)
12-1 Performance of Process Data Communications
12
12-1-1 I/O Response Times for Synchronous I/O Refreshing
Observe the following precautions when you make the calculations.
• Include the NX Units that are set to Disable in the NX Unit Mounting Setting.
• Even if you disabled a channel when you select the channels to use for an Analog I/O Unit, use the
data size for when all channels are enabled to calculate the elements.
• Use bytes as the unit for NX Units that have a data byte size of less than one byte.
For example, the byte size is as follows for an NX Unit with a data size of 4 bits.
4 (bits) ÷8 (bits/byte) = 0.5 (bytes)
• Use the data sizes that you will actually use in the data size calculations.
Refer to this manual, the user’s manuals for individual NX Units, or to the NX-series Data Reference
Manual (Cat. No. W525) for the default values of the Unit data sizes.
This section provides a calculation example for I/O response times.
Calculation Conditions
Calculations are made for the following conditions.
(a) Configuration
The following configuration is used.
(b) With the above configuration, the I/O response time is calculated as the time from when the
CPU Unit processes an external input signal to the NX-ID3343 until the signal is output
from the NX-OD3153.
(c) It is assumed that Tcycle is set to 500 μs.
(d) The default I/O allocations settings are used for the EtherCAT Slave Terminal.
(e) The input filter time for the NX-ID3343 is set to No filter.
(f) The power supply design conditions are not considered in this calculation example.
Calculation Precautions
Calculation Example
NJ-series
CPU Unit
Built-in EtherCAT port
EtherCAT Slave Terminal #1
NX-
ECC201:
1 Unit
NX-
ID3343:
8 Units
NX-
OD3153:
8 Units
NX-
AD4608:
1 Unit
NX-
DA3605:
1 Unit
End Cover
NX Units
EtherCAT Coupler Unit
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