Hello, new BBX32/OB Control user here, but not new to CNC use. I build Centroid Acorn controllers and I use Centroid CNC12 on a daily basis on my machine. I've also used ShopBot, Mach3, and UCCNC. I'm currently rebuilding a small CNC for a customer and he needed a inexpensive solution for controlling it (original controller was MIA). I came across the BlackBox X32 unit and thought that it would be a good solution for him, so that's what we decided on. I've got it set up and working well, but there are some unconventional (to me) use issues that I wanted to check on with the OB Control/GRBL experts. ;-) Negative space machine coordinates... first time I've come across that, but I can deal with it. For the customer that is a total newbie to CNC, it won't make a hoot of difference. It's just not my preference and not the way any other system I've use operates, but on this little machine, homing to the max axes is good, as it moves the gantry to the rear for easy part placement previous to setting work coordinates. My main issue at this moment is the commands that are used with the axes drop down GOTO commands. One issue seems to be a possible bug. I and the customer would prefer to work in inches (yes, barbarian units), so I've set a startup command for G20 and select the inches DRO. What I'm seeing with the GOTO commands, is that they use what I assume is the switch pull off distance ($27), which is set to 2mm. When one of those GOTO options are used, instead of converting the $27 value of 2mm to inches, it uses it as 2", and goes there instead of what should be 0.079mm. So, any of these commands go to 2" away from the intended position. Example of one of the GOTO codes in the list... GOTOZERO (Z Machine Coord, XY Work Coord)(G53 G0 Z-2.000, G0 X0 Y0, G0 Z0)(Retract Z to Machine Coord). This rapids to machine Z -2" and then to work X0 Y0. If you use the GOTO Machine for all three axes, it rapids to -2" on all. Should the program check for this situation, and if so, make the conversion, or issue a G21 at the right point and then revert back to G20? The other issue with the XYZ commands, is the Z axis last position. In the example above, why would you finish that command with G0 Z0, which will place Z axis wherever the Z work coord was/is set at, which could be the surface of the material or worse, the spoilboard when the material is in place! That's an accident in waiting. Leaving the Z axis at machine zero is the preferred method, if homed properly at the max +/up, for the Z. Any of the GOTO commands that are combined X Y movements should first take the Z to machine home (G53) and leave it there. If you want to move the Z down to Z0, do it only with the Z axis GOTO options afterwards. The last GOTO option in the gotozero XYZ list is grayed out most of the time. I've seen it enabled from time to time, but not sure how or what makes it available to click on. I have used it, but as with the other options, when in inch mode, it reads the $27 as 2". In the end, I won't have to deal with this, but I will be the first call made when a crash happens. ;-) I'm sure that some of this is due to the rigid use of mm, and not having a true separation of the two internally (set at install or config time), and my 20+ years of other control systems. And yes, all job files will have the needed setup commands in the post processor. Scott
Ok, thanks. Still would be nice to be able to just put it in inches and have the conversion made. The option to be able to edit/add to those menu items would be great. G0 Z0 (or even 5) is not good. By leaving it in mm, I can see him using MDI (terminal command line) and enter something normal like G0 X3 and getting 3mm instead of 3". I'll have a bit of tutoring to do. Scott
