Calculating The Minimum Safety Task Period - Omron NX-SID Series User Manual

4 Calculating Safety Reaction Times
4-2-3

Calculating the Minimum Safety Task Period

This section describes how to find the minimum safety task period.
Safety Control Systems on EtherCAT Networks
The minimum safety task period depends on the communications setup of the Slave Terminal.
 When DC Synchronization Is Set in All of the Communications Setups of the
EtherCAT Slave Terminals to Which the Safety Control Units Are Connected
The minimum safety task period is displayed by the Sysmac Studio as the Minimum safety task
period.
 When Free-Run Refreshing Is Set in Even One Communications Setup of the
EtherCAT Slave Terminals to Which the Safety Control Units Are Connected
The minimum safety task period is calculated by adding a correction to the value displayed by the
Sysmac Studio as the Minimum safety task period.
Use the following formula to find the value of the correction.
Correction = 11.4 ms
If the value of the correction is less than 0, use 0 as the correction.
Precautions for Correct Use
If you change any of the following values, the minimum safety task period will change. Check
the minimum safety task period again.
• Safety program execution time (This time depends on the sizes of the programs and the
function blocks that are used.)
• Number of connections to Safety I/O Units
• Task period of the NJ/NX-series CPU Unit
• NX bus refresh cycle for EtherCAT Slave Terminals
Version Information
The minimum safety task period has been improved for combinations of NX-SIH400 version 1.1
or later and NX-SL version 1.1 or later.
Safety Control Systems on EtherNet/IP Networks
The minimum safety task period is displayed by the Sysmac Studio as the Minimum safety task period.
Precautions for Correct Use
If you change any of the following values, the minimum safety task period will change. Check
the minimum safety task period again.
• Safety program execution time (This time depends on the sizes of the programs and the
function blocks that are used.)
• Number of connections to Safety I/O Units
4 - 6
− 2 x EtherCAT communications cycle
NX-series Safety Control Unit User's Manual (Z930)