steps per mm for Z axis

Bertie-Basset

@dougal1957 said in steps per mm for Z axis:

@bertie-basset said in steps per mm for Z axis:

23HM22-2804S

looking at the specs for those motors there are 2.8 amps so your string in the M906 should I think be around 2000 and not the 800 you have set.

@Dougal1957 Yes as @Arnold_R_Clark said i forgot to add i did try putting the amps up

Bertie-Basset

@markz

thanks good point, i though i had checked that, as everything appeared to move in the right direct when i changed the steps per/mm but i will re-check.

Bertie-Basset

@markz said in steps per mm for Z axis:

@bertie-basset I have almost the same settings you do for the same hardware (other than I've got 1.8 motors), other than the current. If correcting the max current doesn't work you might check and make sure each Z motor is actually moving in the direction you think (you can move them individually to test). If one Z motor is going the other direction...

I re-checked they all run in the correct direction....

fcwilt

@bertie-basset

Well if they are moving satisfactorily other than the distance moved you merely need to adjust the Z value in the appropriate M92.

Issue a command to move Z by 100mm. Measure how far it actually moved. Then compute the new Z value using the ratio of the two distances.

New Z Value = Current Z value * (100 / distance actually moved) .

Repeat as needed until satisfied.

Frederick

Bertie-Basset

@fcwilt said in steps per mm for Z axis:

@bertie-basset

Well if they are moving satisfactorily other than the distance moved you merely need to adjust the Z value in the appropriate M92.

Issue a command to move Z by 100mm. Measure how far it actually moved. Then compute the new Z value using the ratio of the two distances.

New Z Value = Current Z value * (100 / distance actually moved) .

Repeat as needed until satisfied.

Frederick

In theory yes, in reality NO.

As i said in my original post when you put the required number to get the amount of travel required, the motors dont move they just sit and whine, slowly bring the number down until you get the motors to move (even over 2amps) and the distance traveled is less than the amount requested. I know the math its just not doing what its should be doing which is why im scratching my head.

droftarts

@bertie-basset Your motor config:

; Drives
M671 X-30:150:330 Y-10:350:-10 S15           ; pivot points
M569 P0.0 S1                                 ; physical drive 0.0 goes forwards
M569 P0.1 S1                                 ; physical drive 0.1 goes forwards
M569 P0.2 S1                                 ; physical drive 0.2 goes forwards
M569 P0.3 S1                                 ; physical drive 0.3 goes forwards
M569 P0.4 S1                                 ; physical drive 0.4 goes forwards
M569 P0.5 S1                                 ; physical drive 0.5 goes forwards
M584 X0.0 Y0.1 E0.2                          ; set drive mapping
M584 Z0.3:0.4:0.5                            ; ser drive mappiing for z axis
M350 X16 Y16 Z16 E16 I1                      ; configure microstepping with interpolation
M92 X128.50 Y128.50 Z3200.00 E395.00         ; set steps per mm
M566 X900.00 Y900.00 Z60.00 E120.00          ; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E1200.00      ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z20.00 E250.00          ; set accelerations (mm/s^2)
M906 X800 Y800 Z800 E800 I30                 ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                      ; Set idle timeout

I'd say M566 Z60 is your problem. You are trying to start the motors too fast, and larger motors have more inertia, so can't spin that fast straight away. The high number of steps per mm doesn't help either. Try M566 Z10 and work up from there.

Ian

Bertie-Basset

@droftarts

thank you that is a great spot. i didnt think of it as that is just what the config tool spat out.

i will test now and report thank you again.

fcwilt

@bertie-basset said in steps per mm for Z axis:

As i said in my original post when you put the required number to get the amount of travel required, the motors dont move they just sit and whine, slowly bring the number down until you get the motors to move (even over 2amps) and the distance traveled is less than the amount requested. I know the math its just not doing what its should be doing which is why im scratching my head.

Well the 0.9 steppers are contributing a bit to the the problem, having a bit less torque and requiring twice the steps/mm.

The suggesting regarding acceleration may be spot on.

Frederick

Bertie-Basset

@fcwilt @droftarts

thank you for the pointers I dropped the acceleration down to 10 then 5 and still no joy.

i fitted a set of T8 leadscrews that are not long enough but everything works just fine with them...

fcwilt

@bertie-basset said in steps per mm for Z axis:

@fcwilt @droftarts

thank you for the pointers I dropped the acceleration down to 10 then 5 and still no joy.

i fitted a set of T8 leadscrews that are not long enough but everything works just fine with them...

So you were able to drop the steps/mm from 3200 to 800?

I've never used 0.9 steppers but I have, in the past, used T2 lead screws without issue other then a slower max speed.

Were you trying to move at max speed? If so did you try any slower moves?

Frederick

Bertie-Basset

@fcwilt

yes i was able to drop to 800 and i tried running them very slowly that didnt help, i will see if i can get a full set of T8 leadscrew via Amazon

Bertie-Basset

And i just this minute got it to finally work

I Think i had a combination of issues, while messing about with M203 I had at some point set the max speed of the Z axis to 1800.00 instead of 180.00 and I hadn't noticed, that in conjunction with M566 being too set too high compounded the problem.

i have managed to get it working with the following

M203 Z180.00 ; set maximum speeds (mm/min)
M566 Z10 ; set maximum instantaneous speed changes (mm/min)
M350 Z32 ; configure microstepping
M92 Z 6400 ; set steps per mm
M201 Z20 ; set accelerations (mm/s^2)
M906 Z2000 ; set motor currents (mA)

Thank you to everyone for their input i will mark this as solved