newb looking for help with pulse timer

New to arduino but have a deep background in electrical and some in PLC.

I would like to implement an arduino board to detect the pulse of a limit switch that triggers a countdown.

If that trigger does not occur within 60 seconds then change the analog output from high to low.

Purpose of this project would be to alarm out a machine that stops moving after 60 seconds.

If anyone could provide some links or references to get me started, much appreciated.

Likely I would use a relay to send state to a 24v input. Feel free to correct me as I am new.

Have you studied any of the examples in the IDE or written any sketches?

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kmich: change the analog output from high to low.

If it is HIGH and LOW then isn't it a digital output?

kmich: If that trigger does not occur within 60 seconds

use the millis function to get the number of milliseconds since the board was started. Every pass of loop, if the trigger occurs then record that value from millis into an unsigned long variable. Also on each pass of loop compare the current time from millis to the last time you recorded in that variable. If they differ by more than 60000 then it has been more than 60 seconds since you last saw the trigger.

Hi, Welcome to the forum.

Please read the first post in any forum entitled how to use this forum. http://forum.arduino.cc/index.php/topic,148850.0.html

I would like to implement an arduino board to detect the pulse of a limit switch that triggers a countdown.

If that trigger does not occur within 60 seconds then change the analog output from high to low.

The trigger does not occur within 60 Seconds from when?

You will need an input to tell the timer to start the monitoring process.

Tom.... :)

TomGeorge: You will need an input to tell the timer to start the monitoring process.

Good point, possibly I could get that input from its auto on function from PMC, momentary switch.

Machine is a Makino cnc using 24vdc I/O.

Started this out as... Trying to detect the halt of 3 phase motor. My first thoughts to precisely fuse one leg, if it stops the rise in current would blow that leg and let overload protector do the rest.

Friend of mine suggested arduino might do this as well. It does sound interesting, I ordered a starter kit to try.

kmich: Friend of mine suggested arduino might do this as well. It does sound interesting, I ordered a starter kit to try.

I'd suggest not worrying about the specifics of your project until you have your mind round some of the examples. (That said, of course you'll keep the project in mind as you work through the examples, and mentally store some thoughts for when you get to the project.)

There are loads of examples here, and they're all repeated in the IDE itself under File > Examples.

Just curious, is there an arduino emulator for windows?

Search showed some downloads, just wasn't sure about them.

And thank you for your help, Gave me direction for the night.

Haven't seen any that are worth getting.

Is way to easy to just upload your sketch and try things out on the actual hardware.

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Google "speed switch", that's a common application in industrial control, I've used ones made by Red Lion. Usually they sense a pulse from the rotating part and switch when the pulse frequency falls below a preset value. Simple but pricey, you can roll your with an Arduino. http://www.redlion.net/product/speed-switch-ac-powered

edgemoron: Google "speed switch"

Thank you edge, Exactly what I was looking for. Still might be fun to build on down the road though.