Auto-squaring...

[geneb]

I've got a PRT Alpha 96 that I picked up new in 2006. I've been getting more into CNC stuff lately and I'm in the process of building a PrintNC CNC machine - this got me thinking about using a grblHAL2000 on my ShopBot.

I was able to get the controller pinouts from SB and found that the controller supports 14 inputs and 14 outputs. Is there a reason someone hasn't installed an additional end stop switch so an auto-squaring routine could be written?

Thnx!

g.

[EricSchimel]

I did it back in the day using the Shopbot relay board

https://youtu.be/RGEmztTTnIE

You could do it the way that I did, or you could also run the step pin for whichever motor you want through a relay too.

[geneb]

That's really interesting, thanks! I don't know that my PRT Alpha control board has that daughter board with the X motor link jumper. I'll have to do some digging to see if I can find it.

Could I get the SBP code that you wrote to do the alignment?

Thanks!

g.

[EricSchimel]

It’s been years since I did that. It shouldn’t matter what kind of board you have. If you don’t have the pin like I did on mine you can just find the step pin for whatever driver you want to top. If the driver doesn’t get any step signals it won’t move. If you run that through a relay you can control when your motor gets a step signal or not.

The code was really simple actually. All it did was a normal home. Then it would move one stepper a pre-defined amount to square it.

Eventually I added another sensor on the other side and I had the code hunt for the first and second sensor. That was slightly more complex but way more accurate.

I’d give you my code but it has been years since I have run a Shopbot controller and I have since sold my machine.

[geneb]

I'd appreciate that, thanks!

g.

[EricSchimel]

Sorry if I wasn’t totally clear in my last message… what I was saying is that it’s very possible to do what it is you want but it’s been years since I had a ShopBot control so I no longer have any of the code.

[geneb]

D'oh! I misread what you wrote, my apologies. :)

Thanks!

g.