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Posted

Hi electro wizards.

 

Ive been wrecking my brain, and spent hours drawing lines, but my logic reasoning has abandoned me. Help.

 

I’d like to create a circuit where if there is a continuous input power there will be a recurring output power for a preset duration after a preset time. So in effect: 000 1 000 1 000 1. Is this possible using a digital no/nc countdown timer and a no/nc delay timer? The countdown timer remembers the time and will revert back to it when the power is interrupted and revert back to the original preset time if the timer made it to 0 before the power was interrupted. The delay timer just remembers the delay setting and starts counting from 0 the moment power is (re)supplied. 

The two schematics from the timers will be uploaded shortly as Thaivisa appears to have a problem at the moment. 

 

 

 

Posted
3 hours ago, Fruit Trader said:

Multi-function timers - choose your mode.

 

mft.jpg.4aa4fd655af1ba71894f7fefaf7aa6e4.jpg

 

 

The problem is that I need to control the countdown timer from a control panel. The delay timer is once set okay. 

I see my diagram pictures are now visible. Is it even possible to do what I want using these two timers?

Posted

I did something a loooong time ago, sadly I've long lost the original CAD files but here's a .jpg. 

 

You should be able to sort something from this, basically an astable multivibrator using a couple of timers, this one does a 30 second pulse every 30 minutes.

 

 

30 sec every 30 min timer.jpg

 

EDIT How it works.

In the initial state both timers are off and contacts as in the diagram.

  1. When power is applied the load gets power via K2 4/12 and K2 starts timing powered via K1 4/12.
  2. When K2 times out it removes power from the load and powers K1 via 5/9.
  3. When K1 times out it removes power from K2 (turning on the load again) which also removes power from K1.
  4. K2 is now being powered via K1 4/12 starting the sequence over.

I hope, it's a long time since I did this.

 

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Posted
11 hours ago, Gulfsailor said:

The problem is that I need to control the countdown timer from a control panel. The delay timer is once set okay. 

I see my diagram pictures are now visible. Is it even possible to do what I want using these two timers?

I am guessing the TEH48B is a panel mount countdown timer with memory and that you require it to be the off time for a continuous on/off cycle.


Hopefully TEH48B will reset successfully when AH3-3 times out. Something like this maybe? :-

 

timer.jpg.11e16609e2e19aca213ef0201f9d5573.jpg

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Posted

Look. Those are the threads which gives me the warm memories ????
I see the solution has been discovered by the poster.  Super!

 

When reading the original post, fantastic to read about those electro-mechanical switches, especially the ah3-x timers.

Somewhat nostalgia from the time long before the microprocessor became common. They existed, in fact I was working with PLCs back then for a while but mechanical was still used.

 

For the OP, many solutions and many uses I have been using came trough my head.

Timers I used in the hallway for the staircase lights and the shower ventilation.

 

Would share this:

I did make my own 'countdown' counter/timer by using a motor with a revolution of 2 per minutes (you remember those disco balls and the program motor for the laundry machine).

For a model I wanted a flashing light ,one flash every 15 seconds. 

On the motor a wooden disc was mounted, with two notches. And a micro-switch mounted.

0000100001000010... ????

 

 

When the power was cut, motor stopped. and so was the 'countdown' of the 15 seconds and when the power came back countdown continues.

Does the teh48b the same? I never used that one.

 

Posted

One more .

 

As I was making a astable multivibrator with two caps and two transistors and a few resistors granddad was here and he said;

''When I was younger I made such thing with a window wiper motor from my 2cv and a wooden board with fat polished bolts on a 'arc like path' mounted where the wiper arm moves along.  Live wire on the wiper arm and the bolts connected to (incandescent) colored light bulbs. For the local disco. A band from the UK, some rascals with long hair, was coming that next weekend''

 

He told me many stories but that one is gold to me.

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