Omron NX102 series User Manual

6-23
6 Process Data Communications and SDO Communications
NJ/NX-series CPU Unit Built-in EtherCAT Port User’s Manual (W505)
6-2 SDO Communications
6
6-2-4 Minimum Message Response Time for SDO Communications
The minimum message response time for SDO communications is the time from when the SDO com-
munications instruction is executed in the user program until execution of the instruction is completed.
When the instruction is executed in the user program, the master sends a frame to the slave in the sys-
tem service. When the slave receives the frame, it processes it. When the slave completes processing,
the master receives a response from the slave to complete execution of the instruction.
Additional Information
The minimum message response time depends on the unused time in task execution, slave
SDO size, and slave SDO processing time. In the timing chart below, the time from when the
SDO communications instruction is executed until execution of the instruction is completed
should be used for reference only.
The calculation formula for the minimum message response time differs between when the task
period of primary periodic task is smaller than 4 ms and when the task period is 4 ms or longer.
 When the Task Period of the Primary Periodic Task Is Smaller than 4 ms
*1 The slave SDO processing time depends on the slaves. Refer to the manual for the slave.
*2 Round up the calculation result in parentheses to make an integer.
The transmission size is determined by the task period of primary periodic task as shown below.
6-2-4 Minimum Message Response Time for SDO Communications
NX-series CPU Units
Minimum message response time (ms) = Task period of the task that executes the SDO communications
instruction
+ (Slave SDO processing time
*1
/Task period of primary periodic
task)
*2
× Task period of primary periodic task
+ (SDO response data size/Transmission size)
*2
× Task period of
primary periodic task
Task period of primary periodic task Transmission size
125 μs 64 bytes
250 μs 128 bytes
500 μs or longer 256 bytes

Omron NX102 series Specifications

General

Brand	Omron
Model	NX102 series
Category	Controller
Language	English