Hello, and thanks in advance for any insight.
In one sentence, the problem I'm experiencing is that I'm getting unexpected and alternating values for center point autolevel matrix.
In greater detail:
I’m using a CoreXY type printer with Marlin 2.0.3 software installed on a Robin Nano control board and I’m trying to get a BLTouch to work correctly and consistently.
When I issue successive “G28”, “G29” sequences, I get different results for the center point of the matrix:
1st “G28”, “G29” sequence, center point = 0.00 (+/- 0.01mm),
2nd “G28”, “G29” sequence, center point = +0.21 +/- 0.01mm,
3rd “G28”, “G29” sequence, center point = 0.00 (+/- 0.01mm),
4th “G28”, “G29” sequence, center point = +0.21 +/- 0.01mm,
...
Results will continue with this pattern indefinitely.
I expected the G29 matrix to be consistent with successive measurements as long as there was no physical change made to the bed.
I also expected the center of the G29 matrix to be consistently very close to zero since both the “home” and the center of the autolevel matrix are usually at the same x,y location (I circled it with marker on the bed to be sure).
For troubleshooting:
I have replaced the probe (I was using a clone, but I’m now using a genuine BLTouch) with no change in behavior.
I have replaced the cable with no change in behavior.
For consistency, all tests are run without heating either the bed or the nozzle so there is no influence from thermal expansion.
Has anyone else experienced this? Am I mistaken that the center of the matrix will normally be very close to zero since the center of the autolevel matrix is usually in the same xy location as the location where the "home" Z reference height was just measured? Am I mistaken that successive applications of G29 should result in the same matrix?
