# Square D timer



## John Valdes (May 17, 2007)

I cannot fully explain this to you from your description only. But every solid state timer I have ever used does not use a steady power source and gets triggered from another source.
Timers in come in two flavors. "On Delay" and "Off Delay" 

When the timer gets power input to terminals 2 and 7, the timing function starts with an "On Delay" timer. When power is removed from terminals 7 and 2 the "Off Delay" timers starts its time out. 7 & 2 are the power input on the timer block. ( cube block for relays and timers)
Thats it. Now just figure what you want your timers to do and draw it out first. Make sure it works on paper first. Once you are satisfied your drawing will work, you can start building your control system. Have Fun!

Ps..........Why the ice cube relays?


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## subelect (Nov 25, 2007)

Thanks John.
The ice cube relays are installed because I have "repeater" lights at different stations. One set of lights at the outside payloader operator ramp so he knows that he is not dumping material into the wrong location, one set of contacts for the control room operator to back up his camera as well as the conveyor control ckt. 

I have always had relays/timers that only have one source of 110 volts, but when I was looking at the simple description that comes with the timer, it looked like there was a steady supply and a separate trigger signal necessary. 

I will look at it again tomorrow.
Rick


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## John Valdes (May 17, 2007)

subelect said:


> Thanks John.
> The ice cube relays are installed because I have "repeater" lights at different stations. One set of lights at the outside payloader operator ramp so he knows that he is not dumping material into the wrong location, one set of contacts for the control room operator to back up his camera as well as the conveyor control ckt.
> 
> I have always had relays/timers that only have one source of 110 volts, but when I was looking at the simple description that comes with the timer, it looked like there was a steady supply and a separate trigger signal necessary.
> ...


If it's an "off delay" timer, it does not start timing until power is removed.


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## don_resqcapt19 (Jul 18, 2010)

Many time delay relays require an "always on" power source for some of their timing functions. The one I normally use has 21 timing functions and 12 of those require always on power.


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## John Valdes (May 17, 2007)

don_resqcapt19 said:


> Many time delay relays require an "always on" power source for some of their timing functions. The one I normally use has 21 timing functions and 12 of those require always on power.


You are correct. He did not mention he had anything special. My responses were based on a simple solid state timer with base. :thumbsup:


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## MDShunk (Jan 7, 2007)

John Valdes said:


> You are correct. He did not mention he had anything special. My responses were based on a simple solid state timer with base. :thumbsup:


I don't know if I've ever seen very many 8 or 11 pin timers that didn't take a constant hot. The potted hockey puck style seldom do, but the socketed variety seems to nearly always take a constant hot.


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## tommu56 (Nov 19, 2010)

PLC or no PLC that is the question??????
If you are buying more than 4 timers
I would save them some cash and put in a micro logic 

just my opinion,


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## subelect (Nov 25, 2007)

It was actually a simple job.
I set the timer for "on delay" and ran the maintaining ckt. thru the NC contacts on the timer. The operator can hold the "start" button in to run the conveyor, but if the condition still exists, the contactor will not stay latched. 
thanks for the advice.
Rick


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