CTU¶
Count-up counter. Increments the counter value CV on each rising edge of
CU. Output Q becomes TRUE when CV reaches or exceeds the
preset value PV.
IEC 61131-3 |
Section 2.5.2.3.3 |
Support |
Supported |
Inputs
Name |
Type |
Description |
|---|---|---|
|
|
Count-up input. Increments CV on each rising edge. |
|
|
Reset input. Resets CV to zero while TRUE. |
|
|
Preset value. The threshold at which Q becomes TRUE. |
Outputs
Name |
Type |
Description |
|---|---|---|
|
|
TRUE when the current counter value CV is greater than or equal to PV. |
|
|
Current counter value. |
Behavior¶
On each rising edge of CU, the counter value CV is incremented by one.
When R is TRUE, CV is reset to zero. The output Q is TRUE
when CV is greater than or equal to the preset value PV.
Typed variants CTU_DINT, CTU_LINT, CTU_UDINT, and CTU_ULINT
use the corresponding integer type for PV and CV.
Example¶
This example counts up with CU held TRUE. After the first scan, CV
is 1 which equals PV, so done becomes TRUE.
PROGRAM main
VAR
counter : CTU;
done : BOOL;
count : INT;
END_VAR
counter(CU := TRUE, R := FALSE, PV := 1, Q => done, CV => count);
(* After first scan: count = 1, done = TRUE *)
END_PROGRAM