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
*1
. In the safety system design, the safety distance is
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 Output
Unit/Slave
Actuator
Safety CPU Unit
Safety Input
Unit/Slave
Safety
Sensor/Switch
(a) Safety
sensor/switch
response
time
(b) Safety
Input
Unit/slave
response
time
(c) Network
reaction time
(d) Safety
CPU Unit
response
time
(c) Network
reaction time
(e) Safety
Output
Unit/slave
response
time
(f) Actuator
response
time
Network Configuration between Controllers
Safety CPU Unit
Safety Output
Unit/Slave
Actuator
Safety CPU Unit
Safety Input
Unit/Slave
Safety
Sensor/Switch
(a) Safety
sensor/switch
response time
(b) Safety
Input
Unit/slave
response time
(c) Network
reaction time
(d) Safety
CPU Unit
response time
(c) Network
reaction time
(e) Safety
Output
Unit/slave
response time
(f) Actuator
response time
(c) Network
reaction time
(d) Safety
CPU Unit
response time
Details of each time element are described in the following table.
8 Calculating Safety Reaction Times
8 - 2
NX-series Safety Control Unit User's Manual (Z930)
Summary of Contents for NX-SIH400
Page 4: ...Introduction 2 NX series Safety Control Unit User s Manual Z930 ...
Page 46: ...Revision History 44 NX series Safety Control Unit User s Manual Z930 ...
Page 108: ...2 Specifications 2 42 NX series Safety Control Unit User s Manual Z930 ...
Page 132: ...3 Installation and Wiring 3 24 NX series Safety Control Unit User s Manual Z930 ...
Page 148: ...4 Safety Control Unit Operation 4 16 NX series Safety Control Unit User s Manual Z930 ...
Page 216: ...5 System Configuration and Setup 5 44 NX series Safety Control Unit User s Manual Z930 ...
Page 306: ...6 Programming 6 90 NX series Safety Control Unit User s Manual Z930 ...
Page 390: ...8 Calculating Safety Reaction Times 8 12 NX series Safety Control Unit User s Manual Z930 ...
Page 412: ...11 Safety Data Logging 11 10 NX series Safety Control Unit User s Manual Z930 ...
Page 504: ...12 Troubleshooting 12 92 NX series Safety Control Unit User s Manual Z930 ...
Page 554: ...l I O Map Settings Appendices A 42 NX series Safety Control Unit User s Manual Z930 ...
Page 623: ...I Index I 1 NX series Safety Control Unit User s Manual Z930 I ...
Page 625: ......