Digital filter
Block name
BD15_DIGITAL_FILTER
ST call
PROGRAM BD15_TEST VAR IN1, OUT1: BOOL; FB: LIB.CORE.V1_0.BD15_DIGITAL_FILTER; END_VAR FB(IN:=IN1); OUT1:=FB.OUT; END_PROGRAM
Library
LIB\CORE
Version
V1.0
Description
The block copies the input IN to the output OUT with a functionality that the OUT value changes not more frequently than every T seconds. This means that the block filters fast input changes, see figure below. The block is used to filter, or debounce, the input signal.
Inputs
| Input | Type | Description | Default value |
| IN | BOOL | Input value | False |
| T | TIME | The block does not change the output OUT faster than once every T secs | 5s |
Outputs
| Output | Type | Description |
| OUT | BOOL | Filtered output signal |
| TRES | TIME | Timeout to next possible change of output (TRES = 0 - the block is ready, TRES > 0 - the block is waiting). |
Application example
The block is used to prevent a digital signal from bouncing. The pulse generator is simulating the bounced signal, at the BD15 block output there is filtered (debounced) signal.