Hello,

I wanted clarification because I keep getting contradicting advice and would like to see what the AAC community thinks.

I have a reflective photoelectric sensor connected to a solenoid and I wanted to find a way to time to cut power to the signal of the sensor after a preset time even if the sensor is still activated until it is no longer activated, and the process restarts when the signal is turned on again after.

The solenoid is currently connected to a pneumatic cylinder and I would like the cylinder to activate when the sensor receives the reflective signal (assuring everything is in the correct position) for a certain amount of time then return back to its original position even with the sensor still on and the process to not restart until the sensor no longer receives the reflective signal.

What would be the easiest way to implement this? I know it's possible with a PLC but is there a cheaper/faster solution?

 

Hello,

I wanted clarification because I keep getting contradicting advice and would like to see what the AAC community thinks.

I know in PLC programming there's a function "Timer Off Delay" that seems to do exactly what I am looking for, but would there be an easier way to implement this? It seems possible with a PLC but is there a cheaper/faster solution?

I have a reflective photoelectric sensor connected to a solenoid and I wanted to find a way to time to cut power to the signal of the sensor after a preset time even if the sensor is still activated until it is no longer activated, and the process restarts when the signal is turned on again after.

The solenoid is currently connected to a pneumatic cylinder and I would like the cylinder to activate when the sensor receives the reflective signal (assuring everything is in the correct position) for a certain amount of time then return back to its original position even with the sensor still on and the process to not restart until the sensor no longer receives the reflective signal.

 

Time delay relay

 

Other than a time-delay relay, a typical solution to generate a signal time delay is the ubiquitous 555 timer chip.
What voltage/current do you need to control?

 

Other than a time-delay relay, a typical solution to generate a signal time delay is the ubiquitous 555 timer chip.
What voltage/current do you need to control?

Need to control 24 VDC. I keep being told time-delay relay would work by some but some say it won't. To clarify, will a time-delay relay work even if the input is not de-energized? Will it be able to turn it off after the preset time until it is de-energized, then energized again?

 

"" will a time-delay relay work even if the input is not de-energized?
Will it be able to turn it off after the preset time until it is de-energized, then energized again? ""

No one can say for sure without seeing a Schematic-Diagram of your System,
Specification-Sheets would be very helpful too.
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.
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I would figure the time delay relay will get you the delay needed but some additional circuitry is probably required to monitor the sensor and provide the logic needed

 

Check out timing diagram of an H3CR-A . The NO relay is active from Pwr on until t. Pwr must be re applied for another cycle. Your sensor must then 'source' pwr, or run another timer to debounce if required.



You may though look at the dynamics of the operation to see if there is another action you can sense, which gives similar, or better results, ie; the object being cylindered upon arrives at its new position.

 

Sounds like you're looking for a Monostable Non-retriggerable Multivibrator circuit.

Here's an old thread from back in 2013.
https://forum.allaboutcircuits.com/threads/non-retriggerable-monostable.134131/

 

Here is a simple 555 circuit I built to control a battery-powered cupboard light. It triggers and turns the light on when power is applied, then switches off after about sixty seconds.