Mach3 motor tuning - ClearPath servos

[flathead]

I just purchased some ClearPath servos to replace the brushed servos/gecko 320s on my mill. I've mounted the ClearPath motors to the machine and have completed the autotune process using the provided software. The motors seem to be amazing to this point, but before I connect them to my BOB, I have a couple unanswered questions - what do I used for the velocity and acceleration numbers in Mach3? Does it matter? I'm thinking the acceleration probably doesn't matter, but wouldn't the velocity setting determine the max speed commanded by Mach3? Should I copy the numbers from the autotuning software? I can't find the answers to these questions anywhere? Lots of videos and post by people using these motors, but no one addresses the motor tuning settings in Mach3. I guess I could just connect them and see, but I'd like to hear from someone who has done this before.

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[wjbzone]

I've been setting up motor tuning for my stepper motors. I set the velocity at 150 in/min, but when I rapid it shows 166 in/min on the screen. Don't know why it goes over the 150. I set the acceleration to get to top speed in under 0.5 second.

[Jim Dawson]

I have worked both with ClearPath SD servos and Mach3, just not both on the same machine. Having said that, Mach3 controls the acceleration and velocity, so you have to have to set the acceleration crazy high (maxed out) on the ClearPath so it is higher than Mach3 will output, that lets Mach3 have full control.

With the ClearPath you can have several different settings for the steps/rev. I don't remember the increments, but I would start by setting the ClearPath at ~2000 then set your steps/inch (mm) in Mach3 to whatever is needed to bring the machine into calibration. If that setting doesn't work well then try a different steps/rev.

[ger21]

I'm thinking the acceleration probably doesn't matter, but wouldn't the velocity setting determine the max speed commanded by Mach3?

Mach3's velocity setting is what is used fore rapid (G0) moves, and is the fastest speed that mach3 will allow that axis to move.
Acceleration is very important, as it has a lot to do with how fast your machine works. If acceleration is too slow, you might never be able to reach the speeds you are attempting. If it's too slow, it can also have adverse affects in Constant Velocity mode.

It's up to you to determine how fast you want the machine to move.
Ideally, you want to accelerate as fast as the motors will allow. But you may find that too high acceleration may cause the machine to shake.

A bit of trial and error is involved.

- - - Updated - - -

I've been setting up motor tuning for my stepper motors. I set the velocity at 150 in/min, but when I rapid it shows 166 in/min on the screen. Don't know why it goes over the 150. I set the acceleration to get to top speed in under 0.5 second.

If more than one axis is moving at a time, then the velocity will be faster.
If only one axis is moving then it may be due to your kernel speed being higher than normal.

[flathead]

Thanks for the input guys

Mach3's velocity setting is what is used fore rapid (G0) moves, and is the fastest speed that mach3 will allow that axis to move.
Acceleration is very important, as it has a lot to do with how fast your machine works. If acceleration is too slow, you might never be able to reach the speeds you are attempting. If it's too slow, it can also have adverse affects in Constant Velocity mode.

It's up to you to determine how fast you want the machine to move.
Ideally, you want to accelerate as fast as the motors will allow. But you may find that too high acceleration may cause the machine to shake.

I understand that. I've tuned my old servo/gecko 320 set up. Just was never happy with it. My confusion is just as to how Mach's settings relate to ClearPath's self tuning system, if they do at all. It's becoming clearer to me now that they don't.

Mach3 controls the acceleration and velocity, so you have to have to set the acceleration crazy high (maxed out) on the ClearPath so it is higher than Mach3 will output, that lets Mach3 have full control.

Now that I've looked at it again tonight, this makes sense. The velocity and acceleration numbers shown in the tuning software after the motor is tuned are not really applicable in Mach's motor tuning page. The numbers shown are only the slow jog settings that the software defaults to once the tuning process is complete. I can't find anything in the software that shows any "tuned" or "max" settings. So, I suppose Mach should be set up just as it was done with my previous set up, just different numbers.

I played around with both the velocity and acceleration numbers in the ClearPath software and jogged the motor around trying to determine how high I could go without faulting the motor. I was able to go all the way up to the motor's max rpm (2320 in this case) and the acceleration up to 20,000 rpm/s without getting faults. This gives me 210 in/min of travel. I was never able to get my previous set up any higher than 120 in/min without constant problems, so this is very encouraging. Hopefully it works as well when controlled by Mach3 and the smoothstepper I'm using.

BTW, I noticed that Mach3's acceleration setting is "in/sec/sec" and ClearPath's is "rpm/sec", so it appears a little math will be required to figure out what the setting in Mach should be. Feel free to let me know if I'm off track here.

[Jim Dawson]

I would just bump up the acceleration in steps in Mach3 until the motor faults or it becomes too jerky, then just back it down a bit. That will give you the best performance without tearing up your machine. Getting maximum smooth performance is best done by experimenting, but a little bit at a time. The ClearPath servos have enough power to break things, where a stepper motor will just decouple and stall.

[ger21]

Mach3
s "motor tuning" isn't really "tuning" at all, they are just settings.

The Clear Path motor tuning is something completely different.

I would just bump up the acceleration in steps in Mach3 until the motor faults or it becomes too jerky, then just back it down a bit. That will give you the best performance without tearing up your machine.

+1.
This is how you do it.

[flathead]

This all makes sense now. Before jumping into this I made the assumption that I would be able to autotune the motors using the ClearPath software, retrieve the "tuned" max velocity and acceleration settings from the software, and plug these numbers into Mach3's motor tuning settings. Now I understand that this is not the case. That would be too easy. Not that its that hard to plug in the numbers into Mach and experiment a little to find acceptable performance. I can do that I'm sure.

But I should say, the ClearPath autotune feature is very nice. It gives you the ability to watch its o-scope during the tuning process. You can literally see the adjustments being made by the software. Its neat to see how the motor performs during the procedure. It also gives you the ability to manually fine tune the motor if you want. I've not tried that at this point though. Before, I had to rely on my ability (more of an inability) to tune the Geckos by ear, which is a complete shot in the dark by comparison to the autotune. That was a real pain and I never got results I was happy with. I'm optimistic the ClearPath set up will perform much better.

Thanks for the input guys