Motor Tuning

[Smitty911]

This could be the wrong Forum, but as I have Geckos and you guys know what your talking about, what the hay.

Ok, here's the set-up Gecko 203V with 425oz steppers, Mach 3.

In the motor tuning of the Mach 3 software, it says adjust the Velocity until the motor sounds good. What does that mean? I have had them running full speed and at lowest speed, the motor just changes tone. Not sure on the torque as these are not bolted to anything. A DYNO would be nice.

Any ideas? these will be on a X-2 Mini Mill.

I talked to Gecko Mariss was quit helpfull about a different set up issus. He did mentioned that once it sounded good???? that the adjust should be tweaked just a bit, to smooth it out.

Thanks

Smitty

[Big John T]

The 203v (I have some) only has one adjustment and that is for slow speed smoothness. I think it changes the number of microsteps. As far as tuning for max speed that is a function of the voltage you supply the 203V and the ability of your software to generate steps fast enough and a few more things in your stepper. The 203V is a very fast drive as it can take up to 350 kHz maximum Step pulse frequency if your computer can deliver it.

For a mill I would be concerned with keeping my stepper torque more than speed so I don't miss any steps as load is applied...

John

[Smitty911]

Thanks Big John T,

I have had them spinning as fast as they will go and slowed the down to a crawl, but what are some baseline settings to start?

Ideas?

Thanks

Smitty

[Big John T]

Well, I'm an EMC2 guy so I can't help with Mach2 you might be better off posting Mach2 questions in the Mach2 forum...

John

[Richards]

As I understand it, the adjustable 'pot' on the Gecko G20x stepper drives adjusts the relationship between the micro-stepping pulses produced by the driver. Somewhere I remember that the insructions said to send a slow pulse train (1/4 turn per second, which is 500 steps per second) to the G20x and then to slowly turn the pot until the motor runs as smoothly as possible. Personally, I've never had to adjust the pot from the factory setting except for some old round-style motors that I had hoped to use. (After seeing how roughly they ran, I put them back on the shelf.)

Without knowing more specifics about your setup, I can't give you any Mach 2/3 numbers to try. Normally, I figure the number of steps that the stepper requires per inch and enter that number in the correct place, then I look at the maximum speed available and pick a number that is about 75% of maximum for the G0 slew rate. Finally, I pick a very conservative ramp rate; i.e., one that takes at least one second to get to speed. With that data entered into Mach 3, I test the motor. Normally, I find that I can greatly increase the ramp speed, but I'm designing things for a CNC router where 1,200 ipm is considered slow.

[Smitty911]

Richards,

If you were in town I'd buy you dinner, you have been the most helpful person in my jouney to make scrap, I mean parts.

Your clear explainations have been extremly helpful and have allowed my to get this far.

I'll start the motor tuning as soon as my X-Y stage show up today. I am assuming that all this should be done while the motors are in place on the equipment used.

Thanks

Smitty

[Richards]

Thanks for the undeserved compliments. I'm just one of the fellow travelers walking along the same path that we're all walking.

As far as installing the motors on the machine and then testing them, I use the opposite approach. I first test all components while they're laying on the test bench. The motors are exercised at various speeds while I watch and listen to them. Then, after I'm familiar with the motors, I install them into their working environment. Contrary to popular belief, most motors (at least the ones that I've used), work better under load than they do while spinning freely on the test bench. Once they're on the machine, I adjust the various parameters until the motors run smoothly and then I go to work using them.