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12 Communications Performance
12 - 4
NX-series EtherCAT Coupler Unit User’s Manual (W519)
The maximum and minimum values of the I/O response time are calculated as follows: The minimum
value occurs when the time lag that is shown in the above figure does not occur.
The elements in the formulas are as follows:
• Tcycle: Task period of the primary periodic task in the CPU Unit
• Edelay: Transmission delay time of the EtherCAT master
• Etxj: Transmission jitter of the EtherCAT master
• Tmax-InTrans: Longest input data transmission time of all of the EtherCAT Coupler Units.
• Tmax-OutTrans: Longest output data transmission time of all of the EtherCAT Coupler Units.
• Tmax-InProc: Longest input data processing time of all of the NX Units.
• Tmax-OutProc: Longest output data processing time of all of the NX Units.
• Tnx-Indelay: Input delay time of the NX Unit
• Tnx-Outdelay: Output delay time of the NX Unit
This section defines the calculation formula elements and describes the calculation methods.
Tcycle
This is the time that is set for the task period of the primary periodic task in the CPU Unit
Edelay
This is the transmission delay time of the EtherCAT master.
Use the following formula to find Edelay.
Etxj
This is the transmission jitter of the EtherCAT master.
The value is 100
μ
s.
Formula: Maximum I/O response time = Tcycle × 2 + Etxj + Tmax-I Tmax-OutTrans
+ Tmax- Tmax-OutProc + Tnx-I Tnx-Outdelay
Formula: Minimum I/O response time =
Etxj + Tmax-I Tmax-OutTrans
+ Tmax- Tmax-O Tnx-I Tnx-Outdelay
Definitions of Formula Elements and Calculation Methods
Formula: Edelay = 1.24
×
Number of EtherCAT slaves
*1
*1. This is the number of EtherCAT slaves on the same EtherCAT network. An EtherCAT Slave Ter-
minal is counted as one EtherCAT slave.
+ 0.09
×
EtherCAT frame length in bytes
*2
*2. The EtherCAT frame length is data byte size that is calculated under the following conditions for
the EtherCAT slaves in the same EtherCAT network.
• If the total data size is less than 64 bytes, use 64 bytes in the calculation.
• For EtherCAT slaves that have both input and output data, use the larger of the input data size and out-
put data size. For example, the EtherCAT frame length in bytes for the following configuration is as given
below.
EtherCAT frame length = 20 bytes + 20 bytes + 50 bytes = 90 bytes
Configuration Example
• Two OMRON GX-series EtherCAT slaves: Data size of 20 bytes/slave
• One EtherCAT Slave Terminal: Input data size of 50 bytes and output data size of 30 bytes
Summary of Contents for NX-ECC201
Page 38: ...Sections in this Manual 36 NX series EtherCAT Coupler Unit User s Manual W519...
Page 46: ...1 EtherCAT Networks 1 8 NX series EtherCAT Coupler Unit User s Manual W519...
Page 56: ...2 Features and System Configuration 2 10 NX series EtherCAT Coupler Unit User s Manual W519...
Page 82: ...4 Part Names and Functions 4 14 NX series EtherCAT Coupler Unit User s Manual W519...
Page 100: ...5 Designing the Power Supply System 5 18 NX series EtherCAT Coupler Unit User s Manual W519...
Page 214: ...9 Setting Up Slave Terminals 9 44 NX series EtherCAT Coupler Unit User s Manual W519...
Page 254: ...11 EtherCAT Coupler Unit Functions 11 30 NX series EtherCAT Coupler Unit User s Manual W519...
Page 278: ...12 Communications Performance 12 24 NX series EtherCAT Coupler Unit User s Manual W519...
Page 340: ...14 Maintenance and Inspection 14 8 NX series EtherCAT Coupler Unit User s Manual W519...
Page 400: ...Appendices A 60 NX series EtherCAT Coupler Unit User s Manual W519...
Page 401: ...Index 1 NX series EtherCAT Coupler Unit User s Manual W519 I Index...
Page 405: ......