Pulsing an output methods?

[joeholick]

I would like to energize an output for say 3 seconds, and then de-energize for 3 seconds, and then re-energize for 3 seconds, and off again for 3, and then repeat this process so on and so forth to continue to happen for about 500 seconds. Any ideas on how the logic could be programmed? I am using a Micrologix 1000 with RSLogix500.

Thanks.
Joe.

 

[Ken Moore]

How accurate does the 3 seconds need to be? Is three seconds plus one scan okay? If so, use a self resetting 3 second timer, and then use the done bit for flip-flop logic.
Search the site for flop-flop logic, there are many examples.

 

[L D[AR2P#0.0]]

Does the output need to be off or on at the end of the 500 secs?

 

[adel1961]

and also i am asking if you need the output to start by off or on ?

 

[mellis]

I'm going to assume you have some upstream conditions that determine when this output should cycle, call it "enable". When this is false, the output is off.

The "enable" causes a 6 second self resetting timer to run.
The "enable" and timer accumulator less than 3 seconds = output on.

This is the simplest way I know to do it.

 

[pal]

Another alternative is a 500sec timer and use a bit address from the timer accumulator ie T4:0/ACC.5 By choosing Different bits you get different flash rates from one timer.
Paul

 

[joeholick]

The 3 seconds doesn't need to be super accurate.

The output needs to be off at the end of the 500 seconds. The output could start either off or on, preferably off.

Yes an upstream input starts the sequence, where can I learn or what do I need to do to learn about the self resetting timer?

How the heck does the flash rate thingy work?? Elaborate or example would be awesome!

Thanks you guys.
Joe

 

[Mickey]

How the heck does the flash rate thingy work?? Elaborate or example would be awesome!

http://www.patchn.com/index.php?opt...&id=61:ab-plc-flasher&catid=20:plc&Itemid=118