Siemens SIMATIC ET 200S Operating Instructions Manual page 43

Method of Operation when the Comparison Value Is Reached, Output Pulse Duration
The diagram below provides an example of how hysteresis works. The figure shows the
various responses of an output with a hysteresis of 0 (= switched off) as opposed to
hysteresis of 3. In the example, the comparison value is 5.
The following settings are assigned for the counter: "Pulse on reaching the comparison
value", "No main count direction" and "pulse duration > 0".
When the comparison conditions have been met, hysteresis becomes active and a pulse of
the assigned duration is output.
If the count value goes outside the hysteresis range, hysteresis is no longer active.
When hysteresis is enabled, the 1Count24V stores the count direction.
If the hysteresis range is exited in a different direction to the one stored, a pulse is output.
Figure 2-16
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
Example of How Hysteresis Works
1Count24V
2.6 Count Modes
43