On-/Off-delay

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Short description

The on/off delay function block is used to set an output after a configured on-delay time and then reset it again upon expiration of a second configured time.

 

Connection

Description

input Trg

You trigger the on-delay with a positive edge (0 to 1 transition) at input Trg (Trigger).

You trigger the off-delay with a negative edge (1 to 0 transition).

Parameter

TH  is the on-delay time for the output (output signal transition 0 to 1).

TL  is the off-delay time for the output (output signal transition 1 to 0).

Retentivity on = the status is retentive in memory.

Output Q

Q is switched on upon expiration of a configured time TH if Trg is still set. It is switched off again upon expiration of the time TL and if Trg has not been set again.

Parameters TH and TL

The on-delay time and off-delay time set in parameter TH and TL can be provided by the actual value of another already-programmed function:

You select the required function by the block number.

For information on the validity and accuracy of the time base, refer to the LOGO! manual.

Timing diagram

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Description of the function

The time TH is triggered with a 0 to 1 transition at input Trg.

If the status at input Trg is 1 for at least the duration of the configured time TH, the output is set to logical 1 upon expiration of this time (output is on-delayed to the input signal).

The time TH is reset if the status at input Trg is reset to 0 before this time has expired.

The time TL is triggered with the 1 to 0 transition at the output.

If the status at input Trg remains 0 at least for the duration of a configured time TL, the output is reset to 0 upon expiration of this time (output is off delayed to the input signal).

The time TL is reset if the status at input Trg returns to 1 before this time has expired.

 

Overview