CTD
The CTD function block is a down counter.
If LOAD = TRUE, the counter variable CV is initialized with the upper limit PV. If the CD input has a rising edge from FALSE to TRUE, the counter variable CV is reduced by one as long as CV is greater than zero. If the counter variable CV reaches the value zero, the Q output is set to TRUE.
Inputs
VAR_INPUT
CD : BOOL; (* Count Down on Rising Edge *)
LOAD : BOOL; (* Load Start Value *)
PV : WORD; (* Start Value *)
END_VARName | Type | Description |
|---|---|---|
CD | BOOL | On a rising edge: count down by one |
LOAD | BOOL | TRUE: Set counter variable CV to the start value PV |
PV | Word | Start value |
Outputs
VAR_OUTPUT
Q : BOOL; (* Counter reached 0 *)
CV : WORD; (* Current Counter Value *)
END_VARName | Type | Description |
|---|---|---|
Q | BOOL | TRUE if the counter value CV is 0. |
CV | WORD | Counter variable (current counter value) |
Requirements
Development environment | Target platform | PLC library to include |
|---|---|---|
TwinCAT v3.0.0 | PC or CX (x86) | Tc2_Standard |