Calculating And Verifying The Maximum Reaction Time; Concept Of Reaction Time - Omron DEVICENET SAFETY - CONFIGURATION MANUAL 05-2005 System Configuration Manual

3-3

Calculating and Verifying the Maximum Reaction Time

The last step in designing the network is calculating the reaction time of safety chains. The user himself must
check that the reaction time in all the safety chains meets the requirement specifications.
3-3-1

Concept of Reaction Time

Reaction time is the worst down time among the running devices considering faults and failures in safety
chains. The safety distance is calculated from reaction time.
The reaction time is calculated for each safety chain. The typical combinations of safety chains are as follows:
(1) NE1A-SCPU01 Standalone System
Safety
sensor/switch
(2) Remote Input - NE1A-SCPU01 Output
Safety
sensor/switch
(3) NE1A-SCPU01 Input - Remote Output
Safety
sensor/switch
(4) Remote Input - Remote Output
Safety
sensor/switch
Note: Even if a fault or failure occurs in a safety chain, the output shutoff time is ensured as the maximum
reaction time.

3-3 Calculating and Verifying the Maximum Reaction Time

NE1A-SCPU01 Actuator
Network
DST1-series
I/O Terminal
Network
NE1A-SCPU01
DST1-series Network
I/O Terminal
NE1A-SCPU01 Actuator
DST1-series Actuator
I/O Terminal
NE1A-SCPU01 Network DST1-series Actuator
I/O Terminal
63