CTUD

This device represents an UP/DOWN programmable counter. A rising-edge on the CU ( COUNT-UP) input will increment the counter by one while a rising-edge on the CD ( COUNT-DOWN ) decreases the current value.

Applying a TRUE signal on R input will reset the counter to zero. A TRUE condition on the LD signal will load the counter with the value applied to the input PV ( PROGRAMMED VALUE ) .

QU output becomes active when the current counting value is greater or equal to the programmed value. The QD output becomes active when the current value is less or equal to zero.

As specified in the IEC / CEI 1131-3 standard this kind of counter has a counting range espressed by an integer 16 bit variable. This means that this counter can span from -32768 to +32767 .

Plug	Description

CD	A rising-edge on this input will decrement the counter by one

CU	A rising-edge on this input will increment the counter by one

R	Applying a TRUE signal on this input will reset the counter

LD	Applying a TRUE signal on this input will load the counter with the value present at input PV

PV	When the LD pin is asserted, the value applied to this pin will be loaded as current count value. User should use a CONST or IDENT object to enter numerical constant

QU	This output become TRUE when the counting is equal or greater than the programmed value

QD	This output become TRUE when the counting is less or equal than zero

CV	This output reports the current counting value