Stopwatch (Ta)
The value of “On”, ”Off” and “Cnt” can be set/modified in
parameter mode.
Timing diagram
Description of the function
The function increments (Dir = 0) or decrements (Dir = 1)
the internal counter by one count with every positive edge
at input Cnt.
You can reset the internal counter value to '000000', with
a signal at the reset input R. As long as R=1, the output
is 0 and the pulses at input Cnt are not counted.
Output Q is set and reset according to the actual value at
Cnt and the set thresholds. See the following rules for
calculation.
Calculation rule
If the on threshold >= off threshold, then:
Q = 1, if Cnt >= On
Q = 0, if Cnt < Off.
If the on threshold < off threshold, then:
Q = 1, if On <= Cnt < Off.
Caution
The function polls the limit value of the counter once in
each cycle.
Thus, if the pulses at the fast inputs are faster than the
scan cycle time, the SFB might not switch until the
specified limit has been exceeded.
Example: Up to 100 pulses per cycle can be counted; 900
pulses have been counted so far. On = 950; Off = 10000.
The output is set in the next cycle after the value has
reached 1000.
The output would not be set at all if the value Off = 980
Hours Counter
Description of function
A configured time is triggered by a signal at the
monitoring input. The output is set when this time has
expired.
A positive edge (0 to 1 transition) at
input R resets output Q and sets a
configured value MI at the counter
for the duration of the time-to-go
(MN).
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