Switch-on/off delay
Block name
BD14_SWITCHONOFFDELAY
ST call
PROGRAM BD14_TEST VAR IN1,OUT1: BOOL; FB: LIB.CORE.V1_1.BD14_SWITCHONOFFDELAY; END_VAR FB(IN:=IN1); OUT1:=FB.OUT; END_PROGRAM
Library
LIB\CORE
Version
V1.1
Description
The delay block transforms the input signal IN so that each rising edge longer than TON is delayed by TON and each falling edge longer than TOFF is delayed by TOFF. The TRES parameter gives time remaining to the end of delay. The TRES value can be reset by a rising edge on the RESET input.
Inputs
| Input | Type | Description | Default value |
| IN | BOOL | Input value | True |
| RESET | BOOL | Resets the TRES. | False |
| IGNORESTARTEDGE | BOOL | If TRUE the block is not initialised after start. | False |
| TOFF | TIME | Falling edge delay (30 s by default). | 30s |
| TON | TIME | Rising edge delay (30 s by default). | 30s |
Outputs
| Output | Type | Description |
| OUT | BOOL | Output signal |
| TRES | TIME | Time remaining to the end of delay |
Application example
The block is used to smoothe the binary signal, it is actually a digital filter. The most frequent usage is in cascade controllers to delay the activation of a next cascade stage together with delayed switch-off to make the system more stable.
Older versions
Version V1.0 is flagged as BROKEN. It contained an error of IGNORESTARTEDGE input. Valu on this input during firt cycle of program was not reflecter even if the function block was set correctly.