Omron DEVICENET SAFETY - CONFIGURATION MANUAL 05-2005 System Configuration Manual page 68

Example of Maximum Reaction Time Calculation
Example 1: Remote Input - NE1A-SCPU01 Output
Maximum reaction time (ms)
= Switch reaction time
+ DST1-series I/O Terminal input reaction time
+ Network reaction time
+ NE1A-SCPU01 remote input/local output reaction time
+ Actuator reaction time
= Switch reaction time
+ ON/OFF delay (DST1-series I/O Terminal) + 16.2
+ 28
+ 7 + 2.5
+ Actuator reaction time
= 53.7 + ON/OFF delay + Switch reaction time + Actuator reaction time
66
SNC cycle time = 7 ms
I/O refresh cycle = 3.5 ms
NE1A-SCPU01
DST1-series
I/O Terminal
Safety connection (EPI = 7 ms)
network reaction time = 28 ms
Switch
Actuator
DeviceNet
Section 3: Constructing a Safety Network