Chapter 9
201
Logic programming – Function blocks
Off-delay
Using the off-delay, briefly switching off one or both inputs can be ignored and the
Release output remains high. If one or both of the inputs is/are still switched off after
the off-delay has elapsed, then the Release output changes to low.
If the optional Off-delay timer input is used, then the off-delay is only effective if this
input is high. If the Off-delay timer input is low, then switching off one or both inputs
has an immediate effect.
The off-delay is effective in both the dual channel mode and also in the AND mode.
Input A
Input B
Off-delay timer Input
Off-delay timer
Off-delay
Enable output
Status input A/B
The two Status input A and Status input B outputs indicate the internal value on
the two inputs A and B. The outputs correspond to the value on the Input A and
Input B inputs with the following exceptions:
The status output indicates the value for “Switched off”, even though the related
input is switched on (with input mode = equivalent: low instead of high), as the
other input must first switch off before it is possible to switch on again (Release
output changes to high).
The status output indicates the value for “Switched on”, even though the related
input is switched off (with input mode = equivalent: high instead of low), as the off-
delay is active and switching off is currently prevented internally.
Figure 189:
Sequence/timing diagram
for the tolerant dual channel
monitor function block —
AND mode
Figure 190:
Sequence/timing diagram
for the tolerant dual channel
monitor function block —
off-delay
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