Work with probe

andypugh wrote:

I don't now if you included this, but I made a patch to PSNG to switch to machine base units before probing. 
github.com/andypugh/probe-screen-ng/comm...5cf18d2ae14cafb47766

Thank you for this work. I will study it and try to add.

When I developed dual metric/imperial features for my Electronic Lead Screw I made the decision to keep all the units as one type.  In the case of the ELS this was Imperial units because initially I didn't intend to make it dual.  I then added a user settable flag for Metric units.  So the lead screw pitch might be 10 TPI and it would be stored as 0.100.  Each menu entry had a conversion routine so for pitch it didn't convert.  For the TPI display menu it would call an invert function and show 10 TPI.  And for the metric menu entry it called the convert to metric function and displayed 2.54. 
If a user entered in 5mm as the lead screw metric pitch internally although the display remained as 5.00 the data stored was converted by the convert to imperial function and that value was saved to EEROM.

To make the the probe screen work with metric or imperial and respondent to the G20 G21 G-codes the same sort of operation must occur.  If the MDI command is G20 is issued then the entire probe screen needs to be rewritten to display unit in imperial converted from the internally stored metric values.  And ideally the data field should be parsed to measurement values.

The CAD software I use, AlibreCAD, allows this.  If the drawing is configured as metric then entering a value in with the " symbol automatically converts it to metric.    Add mm to a number in an imperial drawing and it's interpreted as metric.  And if no units are specified it uses the drawing default. 
If I go to the main menu and change the drawing units to be imperial then the drawing =11.0ptdimensions are all converted to imperial.  Unfortunately the add on program AlibreCAM created by MECSOFT as a version of their VisualCAM was not as intelligent.  A tool entered as 0.25" is not automatically configured to be 6.35mm.    So if you load an imperial drawing and your tools are metric it thinks that mill is actually 6.35" in diameter.  Very dumb.

Anyway, IMHO,  I believe high end applications should work like this.

verser,
thank you for updating your code.... I have used it for many years. It is great.
Are you going to push it to the master branch, and python 3 ???
Hope so.

This work will need to be done soon.

What is the value of the buttons (1) if the enable measurement is still pressed with an offset?
What does the ERR check mean (2)?
 

jcdammeyer wrote:

To make the the probe screen work with metric or imperial and respondent to the G20 G21 G-codes the same sort of operation must occur. 

There are two ways to do it, I chose the simpler one, which is to switch back to the machine base units before doing moves based on numbers in the INI file.
I did this because the probe screens call numerous G-code files and the alternative approach (multiplying all movements by a conversion factor) would have required many more changes, with no easy way to be sure that I had caught them all.
I based this partly on an assumption that any G-code run in non-base units would contain a units switch in the header lines.