CTUD / CTUDr

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Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Up/down counter.

Inputs

Input	Data Type	Description
CD	BOOL	Enable Enable signal for the drive, Hardware-Enable with 24V signal to X8, Software-Enable command by setup Software, fieldbus or permanently set. Both are required for enabling the drive. counting Internal count pulses, 1 pulse = 1/2^20turn.. Counter is decreased on each call when CD is TRUE.
CU	BOOL	Enable counting. Counter is increased on each call when CU is TRUE.
LOAD	BOOL	Re-load command. Counter is set to PV when called with LOAD to TRUE.
PV	DINT	Programmed The act of performing a sequence of instructions or commands. maximum value.
RESET New start of the microprocessor.	BOOL	Reset command. Counter is reset to 0 when called with RESET to TRUE.

Outputs

Output	Data Type	Description
CV	DINT	Current value of the counter.
QD	BOOL	TRUE when counter is empty (i.e., when CV = 0).
QU	BOOL	TRUE when counter is full (i.e., when CV = PV).

Remarks

The counter is empty (CV = 0) when the application starts.
The counter does not include a pulse When the step gets activated, the action is activated for a single execution, and possibly once again when the step is deactivated. detection for CU and CD inputs.
Use the f_trig or r_trig function A function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. blocks for counting pulses of CU or CD input signals.
CTDr, CTUr, and CTUDr function blocks operate exactly as other counters.
- Exception: All Boolean inputs (CU, CD, RESET, LOAD) have an implicit rising edge The transition of a digital signal from low to high. AKA: positive edge. detection included.

FBD Language Example

FFLD Language Example

In the FFLD Language, CU is the input rung.
- The output rung is the QU output.

IL Language Example

(* MyCounter is a declared instance of CTUD function block. *)
Op1: CAL    MyCounter (CU, CD, RESET, LOAD, PV)
FFLD     MyCounter.QU
ST     QU
FFLD     MyCounter.QD
ST     QD
FFLD     MyCounter.CV
ST     CV

ST Language Example

(* MyCounter is a declared instance of CTUD function block. *)
MyCounter (CU, CD, RESET, LOAD, PV);
QU := MyCounter.QU;
QD := MyCounter.QD;
CV := MyCounter.CV;