4.5 Delays
The delays can be used for delaying edges for a certain time. Two separate timers are available
for the rising and the falling edge.
If the delay times are different, this may result in an edge F1 at time T
11
has a later switching
time T
12
than an edge F2 at the time T
21
with switching time T
22
. In this case, no edge is
switched at the output, as this would result in the input and output being inverted to on anoth-
er.
T
22
> T
12
F
F1
F2
t1
t2
F
T
22
F1
F2
T
21
T
11
T
12
t1
t2
T
22
T
21
T
11
T
12
T
22
< T
12
The delays are implemented both as "retriggerable" and as "non-retriggerable".
Retriggerable means that a new edge (with the same direction) during the processing will
restart the delay, the switching time for the edge will be recalculated ("last edge dominant").
The level of the input and output are not relevant to the calculation of the switching times.
Retriggerable should be selected if, in the case of several consecutive signals with a short inter-
val between them, only the last signal is to be executed, or if, in the case of continuous signals,
brief signal disturbances (flickering) are to be filtered out. The level of the input and output are
not relevant to the calculation of the switching times.
Non-retriggerable means that a new edge (with the same direction) during the processing
will not restart the delay, the originally calculated switching time is maintained ("first edge do-
minant").
Non-retriggerable should be used if an edge is to start a process, and the process should not be
stopped before the end of the delay.
Note:
The units of the set times is milliseconds [ms], seconds [s] or minutes [min]. Internally, the
values for delays are limited to 24 days.
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