Omron NX-SL3300 User Manual page 384

8 Calculating Safety Reaction Times
Safety Control System on CPU Ruck or EtherCAT Network
The minimum safety task period depends on the communications setup of the Slave Terminal.
l When DC Synchronization Is Set in All of the Communications Setups of
the EtherCAT Slave Terminals to Which the Safety Control Units Are Con-
nected
The minimum safety task period is displayed by the Sysmac Studio as the Minimum safety task
period.
l When Free-Run Refreshing Is Set in Even One Communications Setup of
the EtherCAT Slave Terminals to Which the Safety Control Units Are Con-
nected
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 − 2 x "EtherCAT communications cycle"
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.
a) Safety program execution time (This time depends on the sizes of the programs and the
function blocks that are used.)
b) Number of connections with Safety I/O Units
c) Task period of the NJ/NX-series CPU Unit
d) NX bus refresh cycle for EtherCAT Slave Terminals
• If the minimum safety task period calculated according to the process described in this sec-
tion exceeds 100 ms, adjust the above values so that the minimum safety task period will be
shorter than 100 ms.
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.
Therefore, if NX-SIH400 version 1.1 is replaced with NX-SIH400 version 1.0, the safety reaction
time increases, resulting in an error.
Safety Control System on EtherNet/IP Network
The minimum safety task period is displayed by the Sysmac Studio as the Minimum safety task
period.
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NX-series Safety Control Unit User's Manual (Z930)