Controller Reset Switch

What kind of controller is it?

Do you want a program-controlled reset, using a switch connected to a general-purpose input (a soft reset), or one that will work when the program is not running (e.g. after a fault) - which would have to be connected to a dedicated RESET input¹ (a hard reset)?

If you need a hard reset, what are the characteristics of the RESET input?

¹ If there's no RESET input, you may need to interrupt the power supply to reset the controller.

one that will work when the program is not running (e.g. after a fault) - thats exactly what I need. The controller doesnot have a physical ON/Off or reset switch. So I need to connect a external switch in series with the controller power supply (battery backed up) so that the user can manually reset the controller under fault condition.

24Vdc, need to hold the switch for say, 10 secs. This way controller wont reset if someone presses the button accidentally

Use a time-delay on make relay, such as one found here.

You can also eliminate the need for an ON-Delay timer by using a Key Operated switch with Normally Closed contacts. The key can be removed to avoid accidental resetting.

Just hang the key on a hook or attach to operator panel with a chain or cord.

"so that the user can manually reset the controller under fault condition."

Umm, a cheaper alternative might be to fix the program, or hardware problem that causes it to fault in the first place.

GA from me for as near to 100% a perfect answer as one can give with the limited infos given. I would have been happy if I had written it.

It appears that you know your way around PICs and the like......wonderful chips....even without the fish!

It's easy enough: the pushbutton contact starts a non-retentive timer of x seconds. When the timer expires, a reset signal is sent to the controller. If the button is released, the timer resets to zero.

Is this controller discrete or is it embedded in the code of a programmable logic controller?

It might be a good idea to tell us the exact model/type of PIC or controller chip you are using.

I personally would use a debounce circuit on a relay and a timing chip (555 for instance) with a built in timing of whatever the situation requires.......

I think time delay on make relay will be perfect for what I need. Thanks everyone for your comments!