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OT- Simple electronic circuit design suggestions ?

Milacron

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Would like to design a simple 24VDC circuit where one presses a button to engage a relay. When the relay is engaged a second (lighted type) push button lights up and blinks. You then press the blinking button to engage another relay. Once the second relay is engaged, the blinking light goes out, and a third light on the control panel comes on and stays on (not blinking). Both push buttons need to be N/O momentary contact type. Easy or not ?

(it's mostly the "blinking" part that I have no idea how to do ! And of course there has to be a way to shut it all down as well but I can figure out that part)
 
Very simple. The blinking part is a 555 IC driving the LED in the button - completely independent of the button logic.

You can throw the whole thing together with latching relays (or relays wired to latch) and a driver circuit for the button.

Look at:

http://www.electronic-circuits-diagrams.com/lightsimages/1.gif

for the circuit or the blinker.

Or, save yourself a lot of work and simply use a blinking LED (with a suitable dropping resistor). Look here:

http://www.elexp.com/opt_6bid.htm

Alan
 
Couple more options...if there is a PLC, write the logic for the blinking function to be controlled internally.

I think it can also be done with 2 timing relays too if it is to be all hardwired. One on-delay and one off-delay which "toggle" each other.

You'll need a "push-to-test" indicator lamp to be the blinking pushbutton, there is probably an Allen Bradley 800M series that will work.

I have a sample circuit diagram which I think will work...have to wait until later until I can get back to the scanner
 
Don, not sure what the budget is,but a programmable relay might be a good fit. Idec came to mind, but I think Pheonix, Omeron, and Rockwell have them as well. Around $100

http://www.coleparmer.com/catalog/product_view.asp?sku=6552402&pfx=EW

I have not used one personaly, but have seen them in action. Programming is done right from the panel -no software required. This would allow future control needs, changing the rate of the flash, etc.

Luke
 
I was wondering the same thing Bob. If Don could tell us what it does and the order of happening I believe that I as well as others here could do a diagram for him. He could choose the one he likes best to do the job.
 
Me thinks you need a method to interrupt the
24 volt relay in the blinky LED circuit. You are interrupting the circuit (Ground) in the blinky LED but you are not trying to drop out the relay in the blinky circuit. The first relay will be pulled up but no blinky with the non blinky relay pulled, stopping the blinky.
Regards Walt...
 
Left relays gets latched first and blinky goes on. Right relay gets latched second and blinky goes off, steady led goes on. Both relays stay latched until NC switch is pressed.
 
This would be a piece of cake using a little 8-pin microcontroller to run the whole shebang. That might be the way to go if volume is larger than one.

What's the application?
 
May I be so rude as to as what the heck you are trying to accomplish?
Small industrial robot. First relay enables servo controls, second one turns servo power supply on. There is a little more to it than that but this is the only part I need to know about for now.
 
If you do not want the second switch to be operational (armed) until after the first switch is pressed, wire it as shown below. The diode is just to protect the contacts on the first relay. Search radioshack.com for "blinking LED" - they have several starting at $1.39 for part number 276-036. You'll no doubt need a series resistor suitable for 24 volts.

Latchingcircuit.jpg
 
What if you wire the normally closed contacts in the LED 2 circuit into the hold circuit for the LED 1 relay. Then the circuit will reset itself and be ready to recycle with a input from the NO switch in the no blinky circuit. I don't know if pulling both relays up at the same time is wanted or necessary.
Blinky, no blinky I likey.
Don't forget Lock Out Tag Out procedures.
Regards Walt...
 








 
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