====== Digital filter ======

{{:en:mervis-ide:35-help:bd15.png}}

===== Block name =====

BD15_DIGITAL_FILTER

===== ST call =====

<code st-iec>
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
</code>

===== 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.

{{:en:mervis-ide:35-help:bd15_1.png}}

===== 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 =====

{{:en:mervis-ide:35-help:bd15_example.png}}\\


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.