7.2.6 CTUD_INT

Function

CTDU_INT is called an up-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
CU	Var_Input	BOOL	Up-count signal input terminal
CD	Var_Input	BOOL	Countdown signal input terminal
R	Var_Input	BOOL	Reset input, CV clear
LD	Var_Input	BOOL	Load preset value, set CV to PV
PV	Var_Input	INT	Preset value
QU	Var_Output	BOOL	Add counter status
QD	Var_Output	BOOL	Status of the down counter
CV	Var_Output	INT	The value of the current count

Corresponding syntax

• Counting range: -32768~32767
• Whenever CU changes from FALSE to TRUE, CV increases by 1, and whenever CD changes from FALSE to TRUE, CV decreases by 1;
• When CV is greater than or equal to PV, QU outputs TRUE; when CV is less than PV, QU outputs FALSE;
• When CV is less than or equal to 0, QD outputs TRUE; when CV is greater than 0, QD outputs FALSE;
• The upper and lower limits of CV depend on the maximum and minimum values ​​of the positive type specified by the counter (-32768~32767)
• At any time, as long as R is TRUE, the QU output is FALSE, and CV immediately stops counting and returns to 0;
• At any time, as long as LD is TRUE, QD outputs FALSE, and CV immediately stops counting and returns to the PV value

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:

CTUD_INT_1(
    CU:=UP,
    CD:=DOWN,
    R:=RESET,
    LD:=LOAD,
    PV:=1,
    QU=>OUT,
    QD=>OUT2,
    CV=>cVar
);
IF OUT THEN
    IVar:=iVar+1;
    ELSE
        iVar:=0;
END_IF;
IF OUT2 THEN
    iVar2:=iVar2+1;
    else
    iVar2:=0;
END_IF;