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Author Topic: add relays to Break out board schematics  (Read 2465 times)

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add relays to Break out board schematics
« on: May 31, 2017, 02:45:46 AM »
Hello all,
            I have created a break out board schematics it is finished and I would like to add a relay for coolant/flood to pin 17, so when coolant is activated the relay clicks, is the illustration below correct?



Offline Tweakie.CNC

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Re: add relays to Break out board schematics
« Reply #1 on: May 31, 2017, 03:39:55 AM »
You need to connect a protection diode across the relay coil and also check the model / rank of the PC817 opto as their maximum drive current rating varies from 2.5 to 30 mA and this will determine the type of relay you could use.

Maybe better to purchase a ready-made cnc relay board ( ebay from China ) ??

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: add relays to Break out board schematics
« Reply #2 on: May 31, 2017, 03:45:29 AM »
Hi,
I don't think your diagram is correct...the relay coil is permanently energised as you've drawn it.

The relay coil should be in series with the optotranistor, commonly in the collector side.

Craig
My wife left with my best friend...
     and I miss him!
Re: add relays to Break out board schematics
« Reply #3 on: May 31, 2017, 04:15:29 AM »
Hi,
don't know whether this will attach....
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Re: add relays to Break out board schematics
« Reply #4 on: May 31, 2017, 04:21:33 AM »
Hi,
it worked!  The protection diode Tweakie talked about  is D1. You don't really need a resistor in the output circuit, the relay coil is commonly
1kohm and will self current limit.

Craig
My wife left with my best friend...
     and I miss him!
Re: add relays to Break out board schematics
« Reply #5 on: May 31, 2017, 04:47:23 AM »
Thank you for replying.
Tweakie,
This is more like a electronic project I wish to make it myself. Will look into protection diode, thanks.

Joeaverage

I did a test on a bob's pin 17 and gnd using a voltmeter for continuity, after entering Mach3 I measure Pin 17 and gnd no continuity, then I type M08 at MDI voltmeter beeping I get 5v, M09 to disconnect or off.
My output setings are:
Output #1   Enabled  Port 1   Pin17   Activ low = off




« Last Edit: May 31, 2017, 04:49:15 AM by cncfreakcncfrea »
Re: add relays to Break out board schematics
« Reply #6 on: May 31, 2017, 05:08:10 AM »
Ignore the above I was describing a bob using SN 74act245N, totally different to 74Hc14, sorry..




Re: add relays to Break out board schematics
« Reply #7 on: May 31, 2017, 05:24:24 AM »
Hi,
what voltage do you have available? Clearly the 74HC********* has to be 5V and so also the input photodiode of the optocupler.
The relay and the phototransistor don't have to be 5V, in fact better to be 12V or even better 24V. Relays are available with
5V coils but they are pretty small and liteweight and not likely to last long switching 230V to a pump. There are many more 12V
relays and due to industrial use thousands of 24V relay to choose from.

Craig
My wife left with my best friend...
     and I miss him!
Re: add relays to Break out board schematics
« Reply #8 on: May 31, 2017, 07:40:06 AM »
Ok I've just built a simple circuit in scratch, the only diode I have is a 1N4007N, is is ok?

Offline Tweakie.CNC

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Re: add relays to Break out board schematics
« Reply #9 on: May 31, 2017, 07:54:01 AM »
Quote
the only diode I have is a 1N4007N, is is ok?

Yes.

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