Does exist on the market a differentiator device?

[tireminnanzi]

Does exist on the market a differentiator device? Basically connected to a multiway switching to output a pulse of defined length everytime the deviator changes position on/off?

 

[Lucien Nunes]

I understand what you want to achieve and I would have expected to find a product but cannot immediately see a single unit that does this out of the box. To clarify:

• A single output is to be pulsed on both the rising and the falling transitions of the input?
• What should the output do if multiple input transitions occur within the pulse duration?

You can certainly get edge-triggered relays that will output a pulse on either the rising or falling edge, and connect one of each in parallel. But there would be no control of the behaviour for multiple transitions - a single longer pulse would be the unavoidable result.

What is the application?

 

[James]

6ED1057-3BA03-0AA8 | Siemens LOGO! Series Starter Kit for Use with LOGO! 8.3, 230 V ac Supply | RS

uk.rs-online.com

can be configured to do what you require.

 

[Lucien Nunes]

I was thinking more in the £1 category! Obviously it's easy to design and build with discrete logic if one is electronically minded, but perhaps if we know the application we'll get a clearer idea of what level of engineering the OP is looking at.

 

[tireminnanzi]

very fast answering, this blog is really amazing.

Yes something simple in the budget. We are using this new line of products from Bticino brand where the push button is missing, only the multyway switch (great aestetics but poor technics...) so I was evaluating to setup a small differential circuitry, but first I wanted to double-check what is on the market. No problem on multiple pulses management because it's a house-gate opener impulse that doesn't need accuracy in pulse length. I think the edge-triggered relay is a great idea and can fit this application, now I search for one. @James: I think a PLC it's too much in complexity/cost, but thanks for the answer too.

 

[Lucien Nunes]

As an alternative, perhaps you could take a standard Bticino switch mechanism and modify it to include a momentary contact? Or modify the 'click' mechanism or install a spring inside to return the original contact to the 'off' position? Modifications would invalidate the safety approval for electrical power usage, but if you are only operating an extra-low voltage trigger for the gate that might not be a problem.

 

[tireminnanzi]

it's not low voltage it's 230Vac, I found some candidates, but I think they only trigger at the rising edge not at the decreasing edge:

http://www.veltragyu.com/wp-content/uploads/TRE_time_relay_701-706.pdf

https://www.schalk.de/timer-relays-clock-generators/articles/uzr-u4.en.html?file=files/pdfs/db_uzr4_uzru4_en.pdf

Also it seems that the input signal is a dc, and can't be the 230Vac, I think I need to build it up analogically.

 

[Lucien Nunes]

The circuit can be very simple if there is a suitable DC supply of a few milliamps available. Is there a 5, 12 or 24V DC supply on the unit e.g. for a radio receiver, that can be used for the pulse circuit? Can you build small electronic circuits on perforated board? It's going to need about 10 components.

 

[DPG]

The circuit can be very simple if there is a suitable DC supply of a few milliamps available. Is there a 5, 12 or 24V DC supply on the unit e.g. for a radio receiver, that can be used for the pulse circuit? Can you build small electronic circuits on perforated board? It's going to need about 10 components.

I'm thinking a good old fashioned 555 would probably be suitable.

 

[Lucien Nunes]

The trick I think the OP is looking for here is to trigger on both the opening and closing of the switch, so that you just flip it once to open the gate. The 555 is a useful collection of bits that can be assembled to do many things (including what it does best, short the supply rails together when changing state) but I can't immediately see how to make it respond to both switch edges without extra active components.

Does the switch range from Bticino include intermediate switches (4-terminal switches for lighting control with more than two switch positions?) If so, take a look at this possibility:

C needs to be large enough for the unit to reliably respond.
R1 might not be needed, depending on minimum pulse length and threshold voltage of the input. E.g. if the trigger current is much less than the short-circuit current, R1 can be used to extend the pulse available from a given capacitor size.
R2 is only a nicety to prevent the caps being dead shorted by the switch, R2C = 0.1 seconds.