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Author Topic: Max speed Gecko  (Read 5740 times)

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Max speed Gecko
« on: October 29, 2011, 08:59:14 AM »
Hi everybody.
I just bought myself a Gecko G540 to replace my china driver board. And boy does this make a difference! I was running at about 2500mm/min rapid with the china board and now i am running 3750mm/min without missing a single step.
But now i am eager to test the max speed. But i can't raise the speed higher than 3750mm/min. I have set the acceleration to 800mm/min and it does 400 steps per mm.
If i set the speed higher it just changes back to 3750.. Why?

Also have anyone tried to trim the gecko with the potmeter? As far as i can see the steppers run smooth, and it doesn't change if i turn the pot.. I am running at the 2r/s as suggested in the manual for the g540.

Regards Nic

Offline Hood

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Re: Max speed Gecko
« Reply #1 on: October 29, 2011, 09:46:34 AM »
3750 X 400 /60 = 25KHz so if you want to try more Velocity you will need to increase the kernel to 35KHz or more. Be aware though that some computers are not happy if you go too high on the kernel so only use what you need and not more.
Hood
Re: Max speed Gecko
« Reply #2 on: October 29, 2011, 09:54:58 AM »
ahh, yeah I guess i knew that, just needed to rest my head for a while.. Yes i know, but i am just eager to see how fast i can go without loosing steps :)
Re: Max speed Gecko
« Reply #3 on: October 29, 2011, 10:18:11 AM »
Okay, with the kernelspeed set to 45KHz i get 6750mm/min, without loosing steps :)
Damn, if i had just bought a gecko to start with. It is worth all the money...
And that is on my home made router made out of 21mm plywood with real ballscrews and pillowblocks on hardened steel shafts.

Regards Nic

Offline Hood

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Re: Max speed Gecko
« Reply #4 on: October 29, 2011, 10:41:21 AM »
Yes, had the same thing about 8yrs ago, wasnt a Chinese drive but was a poor quality one I bought from eBay, got about 400mm/min before it started stalling. Got a loan of a Gecko to try and instantly could get 6000mm/min (if I recall) and that was with the same power supply etc, only thing that changed was the drive.
It often doesnt pay to go for the cheap options, I certainly learned that :)
Hood

Offline khalid

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Re: Max speed Gecko
« Reply #5 on: October 31, 2011, 04:28:33 AM »
Okay, with the kernelspeed set to 45KHz i get 6750mm/min, without loosing steps :)
Damn, if i had just bought a gecko to start with. It is worth all the money...
And that is on my home made router made out of 21mm plywood with real ballscrews and pillowblocks on hardened steel shafts.

Regards Nic
Hi Nic , replace the screw with rack and pinion and you will fly with extreme speed... Actually the one disadvantage is G540 always run with 1/10th microstep...Microstepping is not user selectable...
Re: Max speed Gecko
« Reply #6 on: October 31, 2011, 06:02:01 PM »
Hi.
Hmm.. I don't think i need more speed for now. It's a small machine and at 3750mm/min I get the speed I need. I just wanted to test the maximum speed for fun :)

Offline RICH

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Re: Max speed Gecko
« Reply #7 on: November 01, 2011, 06:49:37 AM »
Quote
I just wanted to test the maximum speed for fun

Not for fun, but rather part of tuning to find where to set the max velocity and acceleration that one should use.
Remember that torque drops off as stepper speed increases and what you want is max power which occurs at max velocity at some torque value.
That range is only found through trial and error unles you have a motor curve which you can relate the settings to.

RICH

Offline stirling

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Re: Max speed Gecko
« Reply #8 on: November 01, 2011, 07:44:55 AM »
Actually the one disadvantage is G540 always run with 1/10th microstep...Microstepping is not user selectable...
Not sure why you see this as a disadvantage khalid. Anything much less than 10 and you won't get the advantages that microstepping brings to the party. Anything more than 10 and you're not only into "empty" resolution but also proportionally increasing the chances of microstep "clumping". Marris et al picked 10 for very good reasons.

Ian

Offline khalid

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Re: Max speed Gecko
« Reply #9 on: November 03, 2011, 05:50:48 AM »
Actually the one disadvantage is G540 always run with 1/10th microstep...Microstepping is not user selectable...
Not sure why you see this as a disadvantage khalid. Anything much less than 10 and you won't get the advantages that microstepping brings to the party. Anything more than 10 and you're not only into "empty" resolution but also proportionally increasing the chances of microstep "clumping". Marris et al picked 10 for very good reasons.

Ian

Ian,
This is only because my old computer can't gives more tha 25KHz.. and while running the Gecko in 10 step mode i can not exceed IPM of my Router...
Normally i use 1/2 step mode of SLA7062M based driver.. for wood machining its enough... However, recently i have G203V and i was stuck on speed.. Now i am building the new 4x4 router with Rack and Pinion design and will run it on G540 with 45KHz Kernel speed on new computer...


By the way great product from Gecko drives...