Y Axis Issues

[RChadwick]

I'm setting up my new machine (A Zen Toolworks Plastic-frame CNC), and I wanted to set up 0,0 in the upper left corner, and have what's displayed in the preview window cut out with the same orientation. However, I'm having a nightmare trying to set up the Y axis. I've tried every combination of 'Dir Low Active', and on the motor home/soft limits screen, 'Reversed', and 'Home Neg', and I haven't been able to configure it right. What I want to do is have it home right, move properly when I jog it (Yes, the Y will move opposite, but correct relative to the cutter), and have the DRO numbers move in the positive direction when moving away from 0,0. Is there a setting I'm missing? Am I going about all this wrong?

[Hood]

DRO's will always count positive when the toolpath window shows you  moving left to right for X and down to up for Y, it is convention.

Is there a reason you need to have it working opposite or is it just you want to home to that position? If its the latter then set a home off value equal to your X and Y axis distance and it should all work correctly. What that will do is when you home it will set the machine zero to the lower left and the machine coords DROs will show you are fully positive in X and Y when homed.
Hood

[RChadwick]

Well, I have a fixture for cutting plexiglas sheets, and to hold it in the fixture, I push it into the upper left corner, with hold downs around the bottom and right edges.

[ger21]

Mach3 uses a right hand coordinate system. What you're asking for would be a left hand coordinate system.

How are you creating your g-code? G-code for a RH system will give opposite results in a LH system.

You might be able to set the Y axis scale to -1, but the toolpath display won't show it correctly.

[RChadwick]

Thanks for the responses. I think I didn't have my coffee before my last post. My CNC is set up like an engraver. If home is in the lower left, the tool will be in the way, and I'll have to always jog the cutter out of the way to access the work area. Since this is my first homemade engraver-type of CNC, I was going on my experience with an old New Hermes CNC engraver I used years ago, where 0,0 was upper left.

My G-Code is made by a script in D2NC. It was originally putting the output in the upper right quadrant, but I modified it to put it in the lower right quadrant.

I don't want to go down the wrong path, and cripple myself later with things like the toolpath not showing correctly. It's not too late for me to change the fixture, or my G-Code. What's the accepted way of handling this situation?

[BR549]

Machine 0,0 can be anywhere you want it to be.  Most cams allow you set the 0,0 where you need it.  The machine does not care which quadrant you want to work in.

Just a thought(;-) TP

[BR549]

You can always set up the uperLH as machine 0,0 and have the user 0,0 anywhere. If you want to send it to machine 0,0 then use G30, user home then G28.

(;-) TP

[stirling]

If home is in the lower left, the tool will be in the way, and I'll have to always jog the cutter out of the way to access the work area.

Just home top left and set home to be X0,Y100 (or whatever). i.e. whilst home is perhaps more commonly set to be X0,Y0 - it doesn't have to be, it can be whatever you like.

Cheers

Ian