12 Communications Performance
12 - 18
NX-series EtherCAT Coupler Unit User’s Manual (W519)
If a formula rather than a value is given for Tnx-Outdelay in the above table, refer to the user’s man-
uals for individual NX Units or to the NX-series Data Reference Manual (Cat. No. W525) for the val-
ues of the items to make the calculation.
Refer to Calculation Precautions on page 12-9 in 12-1-1 I/O Response Times for Synchronous I/O
Refreshing on page 12-2 for the formula for calculation precautions.
This section provides a calculation example for I/O response times.
Calculation Conditions
The conditions are the same as those for calculating the I/O response time for synchronous I/O
refreshing. Refer to Calculation Precautions on page 12-9 in 12-1-1 I/O Response Times for Syn-
chronous I/O Refreshing on page 12-2 for details.
Unit Configuration and Data Sizes in the EtherCAT Slave Terminal
These are the same as those for calculating the I/O response time for synchronous I/O refreshing.
Refer to Calculation Example on page 12-9 in 12-1-1 I/O Response Times for Synchronous I/O
Refreshing on page 12-2 and Unit Configuration and Data Sizes in the EtherCAT Slave Terminal on
page 12-10 in 12-1-1 I/O Response Times for Synchronous I/O Refreshing on page 12-2 for details.
Calculating the Elements of the I/O Response Times
This section shows how to calculate the elements of the I/O response times.
Because the calculation conditions are the same as for calculating the I/O response time for syn-
chronous I/O refreshing, a description of the required parameters is omitted here and only the calcu-
lation results are given. Refer to Calculation Example on page 12-9 and Calculating the Elements of
the I/O Response Times on page 12-10 in 12-1-1 I/O Response Times for Synchronous I/O Refresh-
ing on page 12-2 for a description of the parameters required for the calculation.
(a) Calculating Edelay
The value of Edelay is as follows:
(b) Calculating Etxj
The value of Etxj is fixed. The value is given below.
Calculation Precautions
Calculation Example
Formula: Edelay = 1.24 × Number of EtherCAT slaves
+ 0.09 × EtherCAT frame length in bytes
= 1.24 × 1 Unit + 0.09 × 64 bytes
= 7
(Unit: μs)
Formula: Etxj = 100
(Unit: μs)
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