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Author Topic: Pretty little lights or something else  (Read 2446 times)

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Offline Sweep

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Pretty little lights or something else
« on: June 13, 2010, 08:00:39 AM »
I am building a circuit board for my machine upgrade which will carry a total of 5-off SPDT relays. The reason for the quantity is because that is the maximum I can fit on my 100mm x 160mm circuit board so I thought I would utilise all the space.
Not really a problem but can anyone suggest what I might use them for  ::)
All my I/O connections are made through 2-off 25pin plugs.

1) Spindle Run
2) Spindle Fwd/Rev
3) ?
4) ?
5) ?

I thought I might mount some signal lamps on my control panel and have one showing program cycle run/stop, and another indicating when a tool change cycle has been initiated but I don't know how, or if it is even possible, to configure outputs to do this kind of thing (a kind of OEM triggers in reverse, I guess).
I could also use one to control a coolant supply, though my machine has neither a coolant system, coolant tray, or drain holes in the table, though I suppose I could control an air solenoid.
So any ideas; practical or pretty, it doesn't matter !

...Sweep

Offline Tweakie.CNC

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Re: Pretty little lights or something else
« Reply #1 on: June 13, 2010, 09:26:55 AM »
Hi Sweep,

At least 1 relay must be reserved for the 'Beer Dispenser'. Essential for good CNC work.  ;D

Seriously though, be careful what you switch with mechanical relays.
Anything which may cause a spark across the relay contacts such as a mains voltage inductive load (spindle) must be adequately suppressed (the type of RC device found across the switch inside mains operated power tools work well) otherwise the resulting spike may well cause a systems crash.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Sweep

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Re: Pretty little lights or something else
« Reply #2 on: June 13, 2010, 10:34:38 AM »
Good call !
I suppose the beer dispenser wouldn't be any more difficult than plumbing in a coolant system. No, in fact it would be easier as there would, obviously, be no need to have any recirculation pipework; a 'total loss' system is, I think, the correct phrase  :)
As far as the relays are concerned, I have the coils fed from an independent 24Vdc supply switched, via optoisolators, from the computers 5Vdc. Diodes are fitted to between each coil feed and 0V.

...Sweep

Offline budman68

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Re: Pretty little lights or something else
« Reply #3 on: June 13, 2010, 02:48:09 PM »
At least 1 relay must be reserved for the 'Beer Dispenser'. Essential for good CNC work.  ;D

Agreed, I already have my screenset modified for it  ;D

Dave

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