7.2.3 CTD_DINT

Function

CTD_DINT is called a down counter, used to accumulate the number of input pulses (0->1 or 1->0) at the input end.

LD graphics

Parameter description

Interface variables	Declaration	Data type	Description
CD	Var_Input	BOOL	Down counter input
PV	Var_Input	DINT	Preset value
LD	Var_Input	BOOL	Load preset value, set CV to PV
Q	Var_Output	BOOL	Counter status, output bit
CV	Var_Output	DINT	The value of the current count

Corresponding syntax

• Counting range: -2147483648~2147483647
• The rest of the syntax refers to CTD_INT

warning

Function block usage requires global declaration of an instance

Example

• LD example is shown in the following animation:

• ST example is shown in the following code:

CTD_DINT_1(
    CD:=DOWN,
    LD:=LOAD,
    PV:=1,
    Q=>OUT,
    CV=>cVar
);
IF OUT THEN
    iVar:=1;
    ELSE
        iVar:=0;
END_IF;