Thread: Mach 3 & G540 Motor tuning

Originally Posted by seafurymike

for some reason Mach 3 seems to want the motor tuning figures inputted as SPI, even with mm set as my units in the global setting of Mach3. Is this normal?

NO. It is steps per unit. Your units are mm's. So steps per mm

Q3. Do i have to enable something to get the G540 in micro-step mode. I have read all the g540 manuals and there is nothing mentioned about jumpers or setting Mach 3.

NO. Geckos are ten micro steps. No choice there. That is what they are.

Greg

EDIT: Do you have a data PDF for the motors that you have? What voltage are you going to run them from?

Hhi Mike
Working your steps out is much easier than you have there.
If it is a 4 to 1 reduction then you do not have to worry about the circumference of the pulleys. Just use the 4 time multiplier.
You haven't said what pitch screw you have so here is the fomula without it.
(200 X 10 X 4) then divide by your screw pitch in mm.
I'll leave it to Greg for the motor question.

Thanks for the feedback guys,

Rod,

No rod on the X-axis, i have it driven by a belt, thus why i used the 75mm diameter of the pulley. So i'm not sure if i can still use your formula?

Greg,

Okay the 34HD101-31 is on my X and Y axis.
The other unit is for my Z-axis.
I will have to measure the pitch on both these axis tonight.(added below)

I don't think i'm going to get good step resolution on the x-axis.

Pitch measurements:
Y- axis measured across 25 ridges, which implied 23 in between the vernier = 95.24mm and diameter of screw of 17.57mm
Z-axis measured across 10 ridges, which implies 8 in between the vernier = 44.85mm and diameter of screw of 15.92mm

So if i'm right:
Y = 2015.959680806383872322553548929
Z = 893.68832619623906162725749394899

/M

Thought if i included some images it might help

Mike

That is a lousy spec sheet on the steppers. For the 8 wire motor I would expect info like contained in the pic below.

Hard to read. Is that 1.8mh? 2amps.

On the info I have I would think 42volts at 2amps. Wired half coil.

For the small motor, this is also an odd set of numbers. Where did you get these motors.

4.3mh 0.6amp 66 volts would be optimal.

With the G540 you have no choice but to go with the same voltage. And 0.6amp.

Greg

motors came from ocean controls here in melbourne.

yep thought as much, wire in series due to 50Vdc limit of G540

thanks for your help

Actually I was suggesting wiring half coil. Not series.

Greg

Hi Mike
Sorry totally missed the belt drive - thought it was a belt drive on a screw.
Your calcs are correct then and the steps per mm are 16.9765416 which is (the inverse of 2.3561925 mm/step) times 10 times 4.

Originally Posted by Greolt

Actually I was suggesting wiring half coil. Not series.

Greg

Yes you did say that and i should read post carefully next time.
Thanks again

Thanks Rod, i will enter this into M3 and try it out tonight

/M

Given the maths for the X axis and the prohibitive cost of changing to screw, i think i will take the spare 4:1 reduction pulleys I have and use this to provide 16:1 reduction.

So the resolution would then be:

14.726215563702155805293640859123 (16:1 reduction)

and

135.81221810508401985611414474455 steps/mm

so this would give:
0.006642 mm/step which i can live with, even with the slower gantry speeds.


Thanks a lot guys for all the feedback and help.
It's good to be able to air uncertainty and try to work through things I should have thought about from day 1.

Greg,

Given 1/2 coil wiring, the current set resistors should still stay a 2k and 600 ohm for both units?

Mike

Only an eight wire motor can be wired half coil. Amps per phase will be the same as if wired series.

Four wire motors, only one way to wire.

When you get these all set up and running the load, you can test to see if half coil is giving you better performance than series.

Half coil only comes into contention because you are not feeding them the absolute optimum voltage. Nothing wrong with that. None of my machines are.

Given the lack of good data on those motors, testing will be the only way to know for sure.

Greg

EDIT: Just looked at the G540 manual. 2k would give 2 amps and 600r would give 0.6 amps

Thanks for the precise feedback Greg, greatly appreciated.