User manual

Detailed descriptions of I/O modules | Digital counter module UR20-1CNT-100-1DO
142 1432790000/03/02.2014Manual u-remote
Hysteresis
It is possible to prevent frequent switching of the output and/
or triggering of the alarm, e.g. if the value of a sensor signal
fluctuates around the comparison value, by setting the hys-
teresis. A range between 0 and 255 can be preset for the
hysteresis. Hysteresis is deactivated with the values 0 and 1.
Hysteresis affects a zero-crossing, overow/underow and
comparison value.
Active hysteresis remains active after the change. The new
hysteresis range is active during the next hysteresis event.
The behaviour of the output for hysteresis 0 and hysteresis
3 is shown in the following diagram for the corresponding
conditions:
Operating principle when counter value ≥ comparison value
Counting value
Output:
Hysteresis = 0
Hysteresis = 3
1
2 3
4 7
5
6
Comparison
value
1 Counter value ≥ comparison value ➝ output is set and hysteresis activated
2 Leaving the hysteresis range ➝ output is reset
3 Counter value ≥ comparison value ➝ output is set and hysteresis activated
4 Upon leaving the hysteresis range, the output remains set because the coun-
ter value ≥ comparison value
5 Counter value < comparison value and hysteresis active ➝ output is reset
6 Counter value ≥ comparison value ➝ output is not set because hysteresis
is activated
7 Upon leaving the hysteresis range, the output is set because the counter
value ≥ comparison value
Hysteresis becomes active upon reaching the comparison
condition. The comparison result remains unchanged during
active hysteresis until the counter value leaves the set hys-
teresis range. After leaving the hysteresis range, hysteresis
is reactivated only upon reaching the comparison condition
again.
Operating principle when counter value = comparison value
Counting value
Output:
Hysteresis = 0
Hysteresis = 3
1
2 3
4 7
5
6
Comparison
value
1 Counter value = comparison value ➝ output is set and hysteresis activated
2 Leaving the hysteresis range ➝ output is reset and counter value < com
parison value
3 Counter value = comparison value ➝ output is set and hysteresis activated
4 Output is reset because of leaving the hysteresis range and counter value >
comparison value
5 Counter value = comparison value ➝ output is set and hysteresis activated
6 Counter value = comparison value and hysteresis active ➝ output remains
set
7 Leaving the hysteresis range and counter value > comparison value ➝
output is reset
Hysteresis becomes active upon reaching the comparison
condition. The comparison result remains unchanged during
active hysteresis until the counter value leaves the set hys-
teresis range. After leaving the hysteresis range, hysteresis
is reactivated only upon reaching the comparison condition
again.