Units setup

[jtb223]

I'm curious to know how others set up UCCNC for different units. I'm new to all of this so I created two profiles, one for mm and the other for inch. It's easy enough to switch between the two for different jobs. I even took advantage of the option to create a desktop icon for each profile. Of course this means that anything that I do in one profile (setting up macros, etc.) needs to be done again in the other profile. Is this common or is there another way to do this?

thanks, Jim

[Robertspark]

I did ask about G20 / G21 here, and didn't really get anywhere .
http://www.cnczone.com/forums/uccnc-control-software/310716-uccnc-g20-g21-g70-71-a.html

At that time, I thought that the issue would be rescaling the units, velocity and acceleration from one unit to the other based upon whatever was coded prefixed within the g-code.

But in hindsight, the alternative way to do this would be to just scale the blended trajectory within the motion planner. The negative side to this would be at present uccnc is not aware if the axis are linear or rotary, they are just units, hence there would be the complexity of scaling the axis trajectory within the motion planner and excluding the rotary axis, then using this as the blended trajectory......

..... its probably easier just to have a few profiles with whatever units you want to work in (linear, imperial, metric or angular) .....
complexity simplified ...... there didn't also appear to be any support for G20 / G21 as I guess most people have a softness for one or the other in their thought process / available tooling and measurement apparatus.

The thing that I've always wondered about is rounding errors with metric leadscrews on imperial setup machines or visa versa..... how big an issue are they really, probably not much in the hobby world in the whole scheme of things, but if you were polishing lenses or reflective mirrors for a telescope could be another matter.

[ger21]

The thing that I've always wondered about is rounding errors with metric leadscrews on imperial setup machines or visa versa..... how big an issue are they really, probably not much in the hobby world in the whole scheme of things, but if you were polishing lenses or reflective mirrors for a telescope could be another matter.

Internally, I would expect UCCNC to calculate to a much larger number of decimal places than the DRO's display, so rounding errors should not really be an issue.

As for scaling, the motion is the simple part.
Where it gets tricky, is that UCCNC would need to convert every value it comes across, wherever that may happen to be. Things like Park positions, and tool change positions.
Have an ATC, and a macro that changes tools. The values in that macro would be in your units of choice, and if the scaling doesn't account for those values, then bang. The only way that can really work is if UCCNC is working in two different sets of units at the same time. Which makes it even trickier.

[Robertspark]

Thanks Gerry, I hadn't considered the homing, ATC etc.... v good point