CTUD (FB)¶

FUNCTION_BLOCK CTUD

Increments and decrements a given value

Bemerkung

Datatype WORD, which is used for PV in CODESYS, does not match the IEC standard, which for PV defines datatype INT.

(* Example declaration *)
CTUDInst : CUTD ;

(* Example in ST *)
CTUDInst(CU := VarBOOL1, CD:= VarBOOL2, RESET := VarBOOL3, LOAD:=VarBOOL4 , PV:= VarWORD1);

VarBOOL5 := CTUDInst.QU ;
VarBOOL6 := CTUDInst.QD ;
VarWORD2 := CTUDInst.CV ;

InOut:

Scope	Name	Type	Comment
Input	`CU`	`BOOL`	Rising edge: Incrementing `CV` by one
	`CD`	`BOOL`	Rising edge: Decrementing `CV` by one
	`RESET`	`BOOL`	`TRUE`: Reset `CV` to 0
	`LOAD`	`BOOL`	`TRUE`: Set `CV` to the start value `PV`
	`PV`	`WORD`	Start value for decrementing / upper limit for incrementing
Output	`QU`	`BOOL`	`TRUE` if `CV >= PV`
	`QD`	`BOOL`	`TRUE` if `CV = 0`
	`CV`	`WORD`	Current counter value