====== CTD ======

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

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

CTD

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

<code st-iec>
PROGRAM CTD_DEMO
    VAR
     BOOL1,BOOL2,BOOL3: BOOL;
    INT1,INT2: INT;
     FB:CTD;
    END_VAR
    FB(CD:=BOOL1,LD:=BOOL2,PV:=INT1,Q=>BOOL3,CV=>INT2);
END_PROGRAM
</code>

===== Description =====

The block acts as a counter counting down to zero from the preset value //pv//.

===== Inputs =====

|Input|Type|Description                                 |Default value|
|CD   |BOOL|Rising edge counts one down                 |False        |
|LD   |BOOL|Sets the counter to its initial value //pv//|False        |
|PV   |INT |Initial value of the counter                |0            |

===== Outputs =====

|Output|Type|Description                                                              |
|Q     |BOOL|State when the counter finished counting (counting finished: //q//=true).|
|CV    |INT |Current value of the counter                                             |

===== Application example =====

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