New to MESA

Nothing said about Australia Post surprises me these days Rod, I have had enough of them. Joined a site that does shipping on behalf and they use DHL so I'll use that in future...

Now, 7i76 number 2 arrived today, note to self: don't bloody fry this one!!!

So I am movin right along. I have all my axis' moving in the right direction (faster and smoother BTW than before with a parallel port!), I have rewired my proxies to have an input each and my limits & homing working.

Last things are:

To get MB2HAL working again
Program HAL to get my Start/Stop/Pause buttons working
Program HAL to get my warning/info LED working

and the most important right now

Get touch off working again.

With my touch off I have a 2.2K water cooled spindle that is grounded through the VFD which is grounded to electrical 240V ground in my house. In my old implementation with my PMDX 126 I had house ground attached to the 126 ground and then my cutters became grounded negating the need for a clip on the cutter. When the cutter hit my touch plate it tripped the input my plate was attached to telling LCNC it had touched thereby setting Z to zero.

I understand I need to do it a different way with the 7i76 due to the sinking inputs but can't quite fathom it out. Do I need a pull up resister in the loop somewhere plus 24V+ or a combination or something else. Can I connect house ground to the 7i76 ground or is this not needed this time? This is the major last piece of my puzzle so I am hoping someone can throw some light on what I'd need... hopefully

Any suggestions for help would be greatly appreciated.

Cheers

In my spaceship plasma build thread there is a complete worked example of red/yellow/green warning lights and the pause/resume code for a 7i76e

From what I can work out it is better to keep the 7i76 ground isolated from frame ground as that is the whole point of its isolated field power. I think it would be better to run a separate power supply (maybe a cheap buck step down from 24 V) and have it switch a relay to apply 24v to your probe input.

Thanks Rod, Not sure how I'd get the touch off to trigger a relay but will look into it. I have found a couple of examples but they rely on a clip to the 7i76 ground attached to the cutter, in my case I run a pseudo tool changer routine that moves the machine to a fixed touch plate to measure tool offset, not something you want a clip attached to the cutter while the machine drags it around and then takes off to cut the job.

I can't believe there isn't anyone who has implemented a clip free solution while using Mesa boards, surely there are people who run touch off plates on their routers. Oh well, looks like I need to pioneer it in my own world......

No eBay APP ID and/or Cert ID defined in Kunena configurationBruce, I was kinda thinking of one of these

But maybe you can find a 48v to 24 volt one and power it off your stepper motor power supply.

I think they have isolated grounds (ie the high and low voltage sides are not tied together). If you used that to switch a relay coil when your probe touches off, you could have the relay to switch 24 volts to your 7i76e input. That would keep everything isolated from your 7i76e.

Rod, I have a spare 24V Din Rail supply that I could put to work, the whole trick would be getting its ground attached to the spindle. I might try connecting the ground to the machine ground for common reference, much like it was when machine ground was attached to the PMDX 126, no harm in trying and only the spare 24V would die if I stuff it up.