Debouncing touch probe signals on PLC target systems (TP-filtering)

Question:
How can touch probe signals (TP-signals) easily be debounced on IEC-target systems?

Answer:
TP-signals are displayed in the target systems at the so-called TP-received-flags (e. g. system variable DFIN_bTPReceived_b) via a positive edge. In case of detection with switching hysteresis or switching debouncing, multiple detection within a short time (debouncing) can be a consequence. Debouncing can easily be executed via series connection of an off-delay (TOF-function block) and an edge evaluation (R_TRIG-function block). Debounce time is determined at the input of the switch-off delay TOF.PT.

The following presentation shows an example: