Worst-Case Reaction Time - Beckhoff EK1914 Operating Manual

Installation
7.5.2

Worst-case reaction time

The worst-case reaction time is the maximum time required to switch off the actuator in the case of an error.
This assumes that a signal change occurs at the sensor and is transmitted to the input. A
communication error occurs at precisely the moment when the signal is to be transferred to the
communication interface. This is detected by the logic following the watchdog time of the
communication link.
This information should then be transferred to the output, but a further communication error occurs
here. This error is detected at the output following a safety watchdog time out and leads to a switch-
off.
This results in the following equation for the worst-case reaction time:
= +
ReactionTime WD WD
max Comm
Example for the calculation of the worst-case reaction time:
=
ReactionTime
max
40
+
RT
Comm Actuator
+ + =
15 ms 15 ms 20 ms 50 ms
Version: 2.0.0 EK1914