Bitzero V2.0 setting Z height 2.5mm too low

[Gwoodward (Guy Woodward)]

I have a problem. I recent updated CM to 6.4 and CC to 7.78 and now when I use the Bitzero v2.0 to set the X,Y,Z it sets Z zero 2.5mm lower than the actual top of the stock. You can tell it is wrong because after probing, and Z raises up, Carbide Motion reports that the tool tip position is Z 21.5mm when it should be 19mm. Also if you goto 6mm above Z Zero its 3.5mm and if you goto z Zero its 2.5mm below the surface. I am having the toughest time trying to do Vcarve inlays and This is really causing as issue. TO be fair I dont know if this issue was with the older software because I never did any vcarve inlays. So I didn’t notice. If it is wrong, I can fix it by jogging Z up to 2.5mm and zeroing Z. Or I can do just Zero using the paper method. But this is impossible when doing Vcarve.

I’m wondering if the baked-in function of Carbide Motion to only probe Z has an incorrect offset for the thickness of the V2 BitZero?

I have checked that I am sending the correct Z-Axis setup up for my machine. I have a 4XXL with upgraded Z Axis so $102=200. any thoughts on how to fix this issue?

[WillAdams (William Adams (Carbide 3D))]

Usually this happens when one positions the BitZero for probing all 3 axes, but then probes only for Z.

Please see:

Using/verifying the BitZero

Here is how I check out the functionality of the machine/BitZero: first check that you have sent the correct Z-axis configuration This can be easily done by jogging down to the wasteboard surface, setting zero, then using the Rapid Position command to lift 6mm above the current zero — measure how much the machine moved — if it’s wrong: open the Log Window go to the MDI (EDIT: Note that it will need to be enabled in options in current versions) and send $$ and check that the Z-axis steps/mm …

[Gwoodward (Guy Woodward)]

if I use the paper method to set Z-Axis then everything is as expected (it retracts to the correct height 6mm when asked to and Z-Zero is perfect… If I set the Z-axis by probing with the bitzero then everything is off by 2.5mm? How do you correct that? If I change the steps in MDI from $102= then it changes both. Anyway to change the default Bitzero Height?

[Chaotica (Joel McKenzie)]

I use my BitZero v2 all the time to set Z-zero & it has not failed me.
Have you checked that Carbide Motion is configured for using BitZero v2?
I have noticed that in Debug Tab of the Machine Settings there is a configuration parameter bitZeroType which should be set for 2.

As Will mentioned above, if you are only probing for Z, then you must place the BitZero v2 with it’s edge guides on top of the surface to be zero’d from. The algorithm is set to use the full thickness including the edge guides for the zero calculation. And yes, the BitZero v2 does not like to sit flat like that - I always gently hold it down while Z-probing to ensure an accurate reading to my surface.

[mhotchin (Michael Hotchin)]

When probing for Z only, you must place the BZ entirely on top of the material. Do not “hook” the BZ over a corner when probing for Z only.