3 ctud, Ctud, Drive plc developer studio – Lenze DDS v2.3 User Manual

Page 307

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Drive PLC Developer Studio

IEC 61131-3 Standard functions

14-15

l

DDS EN 2.3

14.6.3

CTUD

Up and down counter

CU

, CD, RESET, LOAD, QU and QD are of type BOOL, PV and CV are of type INT.

If RESET is valid, the counter variable CV will be initialized with 0.

If LOAD is valid, CV will be initialized with PV .

If positive edge CU is valid, CV will be increased by 1 as long as CV does not cause an
overflow.

If positive edge CD is valid, CV will be decreased by 1 as long as CV does not cause an
underflow.

QU

returns TRUE if CV has become greater than or equal to PV.

QD

returns TRUEif CV has become less than or equal to 0.

CTUD(CU, CD, RESET, LOAD, PV, QU, QD, CV)

Examples
Declaration:

CTUDInst : CTUD;

IL

FBD

CAL CTUDInst(CU:=VarBOOL2, RESET:=VarBOOL32,

LOAD:=VarBOOL4; PV:=VarINT1)

LD CTUDInst.QU
ST VarBOOL5
LD CTUDInst.QD
ST VarBOOL6
LD CTUDInst.CV
ST VarINT2

ST

CTUDInst(CU:=VarBOOL2, RESET:=VarBOOL32, LOAD:=VarBOOL4; PV:=VarINT1);
VarBOOL5:=CTUDInst.QU;
VarBOOL6:=CTUDInst.QD;
VarINT2:=CTUDInst.CV;

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