Input Debounce Time; C.1 General Information On Parametrizing - Festo CPX Series Electronic Manual

C. General information
C.1 General information on parametrizing
C.1.1 Input debounce time
C-4
Basic information
Input debounce times are specified in order to eliminate in-
terfering changes of signal edge during switching procedures
(bouncing of the input signal). For example, mechanical
switches generate brief undesired signal edges during switch-
ing procedures. The signal states which are thereby produced
can cause interference in the control sequence and should
therefore freqeuently be suppressed.
Interfering, undesired signal edges can be suppressed by a
PLC program in the higher-order controller. Interference can
therefore be avoided. With the CPX terminals, undesired sig-
nal edges can be suppressed simply by parametrization.
CPX parametrizing
With the CPX terminals, the input debounce time can be set
with an appropriate module parameter. The possible input
debounce times therefore depend on the particular type of
module. Typical input debounce times are: 0,1 ms, 3 ms
(typical pre-setting), 10 ms and 20 ms.
Method of operation
Changes of edge in the sensor signal will be accepted as a
logical input signal (see Fig. C/1) only when the specified
debounce time has expired.
Festo P.BE-CPX-SYS-EN en 0112NH