Reaction Times; System Reaction Time; Logix System Reaction Time - Rockwell Automation Allen-Bradley 1715-AENTR User Manual

Reaction Times

Sensor Reaction
Time
Input Module
Delay
IMPORTANT The Reset Counters button on the diagnostics tab resets only the
counters that are shown in the 1715 I/O module profiles.
It does not reset the counters that are displayed within the
ControlLogix Add-On Instructions.
The values retrieved from 1715 output modules populate the
diagnostic information. Equivalent input module diagnostic data
is made available by the
Add-On Instructions.
To determine the system reaction time of any control chain, you must add up
the reaction times of all of components of the safety chain.

System Reaction Time

System Reaction Time = Sensor Reaction Time + Logix System Reaction Time
+ Actuator Reaction Time
Figure 67 - System Reaction Time
System Reaction Time
Input Reaction Safety Task
Time Reaction Time
Safety Task Period
Input Connection
+
Reaction Time Limit
Safety Task Watchdog

Logix System Reaction Time

The following sections provide information on calculating the Logix System
Reaction Time for a simple input-logic-output chain and for a more complex
application using produced/consumed safety tags in the logic chain.
Rockwell Automation Publication 1715-UM001J-EN-P - December 2020
Chapter 7 1715 Redundant I/O System in SIL 2 Safety Applications
Output Reaction
Time
Output Connection Output Module
Reaction Time Limit Delay
Actuator Reaction
Time
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