[3.6.0-rc.2] Expansion boards microstep positioning error

leone

Hi all,
before beta.4 there was a positioning error of about one microstep when movements stopped. I'm using now rc.2 but I think it is still an issue for drives connected to expansion boards.

The test I've done is:

steps/mm is 80 -> 0.0125 mm/microstep.
X-axis motor connected to 1HCL. Y and Z are connected to MB6HC.
home all
Run test macro 3 times (no homing in between)

Test macro:

G1 X0 Y0 Z0
M118 S{"User Position "^move.axes[0].userPosition^",Y "^move.axes[1].userPosition^", Z "^move.axes[2].userPosition^"}
M118 S{"Machine Position "^move.axes[0].machinePosition^",Y "^move.axes[1].machinePosition^", Z "^move.axes[2].machinePosition^"}

G1 X10 Y10 Z10 F600
M118 S{"User Position "^move.axes[0].userPosition^",Y "^move.axes[1].userPosition^", Z "^move.axes[2].userPosition^"}
M118 S{"Machine Position "^move.axes[0].machinePosition^",Y "^move.axes[1].machinePosition^", Z "^move.axes[2].machinePosition^"}

What I get echoing the user and machine positions in between each move:

Run 1
User Position 0.00,Y 0.00, Z 0.00
Machine Position 0.00,Y 0.00, Z 0.00
User Position 9.988,Y 10.000, Z 10.000
Machine Position 9.988,Y 10.000, Z 10.000

Run2
User Position 0.0125,Y 0.0125, Z 0.00
Machine Position 0.0125,Y 0.0125, Z 0.00
User Position 9.988,Y 9.988, Z 10.000
Machine Position 9.988,Y 9.988, Z 10.000

Run3
User Position 0.0125,Y 0.00, Z 0.00
Machine Position 0.0125,Y 0.00, Z 0.00
User Position 9.988,Y 9.988, Z 10.000
Machine Position 9.988,Y 9.988, Z 10.000

It's also very strange that from the second run also the Y axis (connected to MB6HC) seems to have a similar problem, while if I connect the X-motor to MB6HC all the returned positions are precise.

Can someone replicate this behaviour? Thanks in advance.

dc42

@leone lease provide your config.g file and any other macro files that it calls.

Is the report still inaccurate if you put a M400 or G4 P100 command between the G1 command and the M118 command?

leone

@dc42 here the files, yes the report is the same with M400 in between.
config.g
test_microstep.g