Flasher circuit using a BD679

[EddyCurrent]

What's the 'brain' function then ? Forgive what may be a dumb question, as I said I'm new to CNC...

This is the info that Bruce is using for his machine, see the Zip file attachment for the Brains.
http://www.mycncuk.com/threads/6565-...2213#post52213

Brains are a feature of Mach3 software, you can get an overview here;

[JAZZCNC]

I had an issue with a PMDX A few months ago with prox switches on Home switches (Inputs) not being pulled to ground and the cure was a small resisistor between ground and the pin. It sounds like you are having a similiar thing so worth a try.?

[ozspeedway]

Jazz... close I think.....

It is now working after receiving an email from Steve @ PMDX. In his email he indicated that I needed to connect the negative from the 24v supply to GND so the transistor had a reference to it. I did that and it works. I now know why Eddy's worked from the start (at least I think I do), his BOB is powered by the same 24v supply as the flasher circuit and therefore the tx already had a reference to the 24v neg side. I am thinking now if I replaced the 24V LED with one suited more to 5v whether it would work without grounding to the supply. However, that would probably be a moot point given that I have a PMDX 126 winging its way to me as we speak and it is powered by 240v.....

Thanks to everyone who ran around in circles with this, I really appreciate the help given

Cheers
Bruce

[JAZZCNC]

Jazz... close I think.....

It is now working after receiving an email from Steve @ PMDX. In his email he indicated that I needed to connect the negative from the 24v supply to GND so the transistor had a reference to it.

Ah ah.!! . . . Assumption being the mother of all F'#&up's me and suspect others presumed you would be doing this as it's a given that you must use the same ground for any circuit to work correctly.!

[ozspeedway]

And with me being a follower and not a guru in electronics I managed to completely miss that principle. Lesson learned I can tell ya because now I just feel like a wally :)

[Wobbin]

Assumption being the mother of all F'#&up's

LOL... when I was fixing drives a while back I had that very phrase on a label on my bench to remind me :-)

No 0v reference - yep, that would do it. We've all been there. Glad you're sorted.

Cheers
Robin