Debounce Filter
Original instructions
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Overview
The purpose of the debounce function is to adapt the discrete input for mechanical switches. The programmable debounce filter can also be used to reduce the transient interference.
CAUTION
UNEXPECTED BEHAVIOR OF APPLICATION - INCORRECT INTERPRETATION OF INPUT DATA
Debounce filters are used to suppress the input recognition in a defined way. Filtering should only be used in a suitable way to prevent too much or undesired suppression of input data.
Failure to follow these instructions can result in injury or equipment damage.
Debouncing inhibits the processing of fast state changes.
The value range for the filter time is 0...255 ms; the value 0 deactivates the debounce filter. The default value in Control Expert is 1.
A debounce filter may be one of the following:
This table shows the parameters for the debounce filter function:
Parameter
Symbol
Valid Values
Unit
Description 
Configuration
Debounce filter type
0: Steady state
1: Integrating
–
Effective range
Group
Organization
Each group 
Configuration
Channel x debounce time (x = 0...15)
0...255
(default: 1)
ms
Effective range
Channel
Organization
Each group
NOTE:
  • Excessive debounce time may cause the loss of effective events.
  • Debounce time ≥ 1 ms is recommended to provide enough immunity from electromagnetic disturbances.
  • The setting of debounce time affects the time stamping accuracy because the recognition of transition is delayed.
Steady State Filtering
A signal change is registered only if the polarity change remains stable for longer than the filter time (each new change resets the filter time):
Integrating Filtering
A signal change is registered only if the time integral of the input signal reaches the programmed filter time considering any polarity change: