Safety Reaction Time; Calculating The Safety Reaction Time - Omron NX-SL3300 User Manual

8 Calculating Safety Reaction Times
8-1

Safety Reaction Time

This section describes the safety reaction time (i.e., the safety response performance) of Safety Con-
trol Units.
The safety reaction time is the maximum time required to turn OFF an output in consideration of possi-
ble failures and breakdowns over safety chains
calculated based on the safety reaction time. For all safety chains, the longest time required to stop
moving equipment from when a safety input was activated must satisfy the required specifications.
*1. The safety chain is the logical connections that are required to achieve a safety function, including the safety
input device, Safety Control Units, and the safety output device.
8-1-1

Calculating the Safety Reaction Time

As shown in the figure below, the safety reaction time is the sum of (a) safety sensor/switch response
time, (b) Safety Input Unit/slave response time, (c) Network reaction time, (d) Safety CPU Unit re-
sponse time, (e) Safety Output Unit/slave response time, and (f) actuator response time. The number
of elements and the duration of time vary depending on the safety chain route.
Basic Configuration
Safety
Sensor/Switch
(a) Safety (b) Safety
sensor/switch
response Unit/slave
time response
Network Configuration between Controllers
Safety
Sensor/Switch
(a) Safety (b) Safety
sensor/switch
response time Unit/slave
response time
Details of each time element are described in the following table.
8 - 2
Safety Input
Unit/Slave
Safety CPU Unit
(c) Network (d) Safety
Input reaction time CPU Unit
response
time
time
Safety Input
Unit/Slave
Safety CPU Unit
(c) Network (d) Safety
Input
reaction time CPU Unit
response time
*1
. In the safety system design, the safety distance is
Safety Output
Unit/Slave
Actuator
(c) Network (e) Safety (f) Actuator
reaction time Output response
Unit/slave
response
time
Safety CPU Unit
(c) Network (c) Network
(d) Safety
reaction time CPU Unit reaction time
response time
NX-series Safety Control Unit User's Manual (Z930)
time
Safety Output
Unit/Slave
Actuator
(e) Safety
(f) Actuator
Output response time
Unit/slave
response time