strange UVW axis behaviour compared to ABC axis

Tricep terry

Hi I'm not using duet as a printer but rather write my own Gcode scripts to move certain axis. Now I came across something strange in the behaviour of ABC axis compared to XYZUVW axis.

I have the same exact settings for the ABC axis and UVW axis, however, if i ran the following code :

M118 S"Start"
G91 G1 A-170.00 B-80.00 C-234.00 D-16.0 F361 ;
M400
M118 S"finished"

It takes exactly 50 seconds as it should.

however if I change it to :

M118 S"Start"
G91 G1 A-170.00 B-80.00 C-234.00 U-16.0 F361 ;
M400
M118 S"finished"

it takes about 1 to 2 seconds.

My guess would be that this has to do with the "cartesian style" mentioned in the config.json file.

The same thing happens for the V and W axis...

Kind regards,

JoergS5

@tricep-terry Hello, I guess it has to do with ABCD being default rotational and UVW being linear axes:

https://duet3d.dozuki.com/Wiki/M584

R parameter: " then RRF 3.2beta3 and later assume UVW are linear and ABCD are rotational."

Tricep terry

@joergs5 That might be it, how should I modify the M584 command then? Should I create a separate M584 line for each axis?

Kind regards,
Max

JoergS5

@tricep-terry I have no experience, but in my interpretation, R0 and R1 settings should be in separate lines and commands.

I would also set speeds for the letters. (Being degrees/min for rotational).

JoergS5

@tricep-terry there is an addional possible reason, but it has to do with U as linear also: the total speed is calculated and limited in the kinematics code. It depends on the distance calculated, which is calculated for rotational and linear axes separately. So A+B+C+D all rotational with D low limits the total speed, but A+B+C rotational + D linear with A,B,C high values do not limit total speed. But this will be fixed by specifying U as rotational, also.

Tricep terry

@joergs5 Hi, your suggestion worked. I changed the S value in the M584 command and now it works. Thanks!

Kind regards,

JoergS5

@tricep-terry that's good news, thanks for telling!