iSV57T-180 VS IHSV60-30-40-48 Servo Comparison

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01 Jan 2022 15:30 #230457 by EragonPower
Hello everyone,
in the last 4 years i've been working on a cnc router on my own, i've changed many things since the beginning, the project is already on it's way and i need only the last few components such as the spindle and the motors. I've looked into cheap servo motors and found the popular ISV57 and settled on it at first. Today looking around on the internet i've discovered it's "bigger brother" the IHSV60, the first thing that jumped to me where the flange difference (Nema 23 for the ISV57 and Nema 24 for the IHSV60) and their power ratings(ISV57: 180W IHSV60: 400W!). Apart from these differences there are some other like the shaft difference, but that's not the problem i've encountered.

I'm split between those two servos, i'd like having more power as my router is quite heavy but i don't really know if it's worth the roughly 500€ more.

Have anyone had any experience with one or both of these servos, and if so what would you recommend?

Thanks in advace to everyone that has any opinion

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01 Jan 2022 19:58 - 01 Jan 2022 19:58 #230470 by 0x2102
Not sure if you want to hear this but I would suggest you skip those small servos and go for their closed-loop stepper motors instead. The small servos can be a pain to tune and the software isn't all that great either.
Last edit: 01 Jan 2022 19:58 by 0x2102.

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01 Jan 2022 20:09 #230472 by EragonPower
I'm looking for servos because of their "constant" torque even at high RPMs as i plan to run this machine at high feedrates

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08 Nov 2022 21:03 #256245 by tincho80
may I ask you, to what feed rates you got it to?
I've got some IHSV60-30-40-48 controlled by a MESA 7i76e and got stuck at very low rates.
Servo Thread is 1'000'000 ns, 5000 steps/rev, ball screw pitch is 5 mm/rev

desired resolution is 0.001 mm and 100 mm/sec feed rate. possible? or anything close to that? need to swap hardware?

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09 Nov 2022 04:33 - 09 Nov 2022 04:36 #256260 by PCW
100 mm/s with a 5mm/turn ballscrew is only 1200 RPM.
This is tough for a low end step motor system but should
be easy for a servo motor.

What is limiting the speed?
Last edit: 09 Nov 2022 04:36 by PCW.
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09 Nov 2022 04:59 - 09 Nov 2022 05:00 #256262 by EragonPower
On my machine I've set the servos to 4000 steps/rev and i run then at a max of 12m/min.
The main limiting factor is that even though the servos datasheet states that it can have a step length/dir setup/dir hold/step space of 2500ns they start to struggle a lot, arriving at roughly 15m/min but with positioning problems, while at low speeds the servos completely missed steps. This with untuned servos at least.

I'm currently using this step timings limiting the machine to a little more than 12.5 m/min:
DIRSETUP   = 3000
DIRHOLD    = 3000
STEPLEN    = 3000
STEPSPACE  = 3000
With a 5mm pitch screw and the servos set to 4000 step/rev @ 48VDC.
Quick note on acceleration, I'm using 1000mm/min² at the moment, and i haven't found any problem even though after tuning the servos i could bump it up a fear bit and try to increase the speed decreasing the step timing. For tuning the servos I've seen this videos:
Basic tuning(more than enough in my opinion):

Advanced tuning(if you want to spend a lot of time but get every bit of performance out of the servos):
Last edit: 09 Nov 2022 05:00 by EragonPower.
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09 Nov 2022 05:56 - 09 Nov 2022 06:24 #256264 by arvidb

Advanced tuning(if you want to spend a lot of time but get every bit of performance out of the servos): <YT link>

He disables gain switching but still modifies "Position control gain 2"? That's a bit strange. I'm pretty sure gain 2 only comes into play when using gain switching. Worse: in the YT comments he suggests tuning the position loop first, then the velocity loop. That's really bad advice. So while he does manage to get a good tuning I'm not sure his method is sane or that he really knows what he's doing. Edit: It's pretty frustrating really, seeing him randomly change values without a clue and trying to come off as someone who can teach others how to tune servos.

For an excellent tuning tutorial I recommend Yaskawa's "Sigma-7 Servo Tuning" tutorial series:
www.youtube.com/playlist?list=PLNAENlyED...QGvDJOps3g88m4auq5h_

Start at "06 - Servo Tuning Basics" and then look at e.g. "10 - Autotuning", "11 - Custom Tuning", and "12 - Tuning for Low Position Error" (and any other parts that look interesting of course!). While the tuning is done on Yaskawa Sigma-7 the parameters and methodology are basically the same with any servo.
Last edit: 09 Nov 2022 06:24 by arvidb.
The following user(s) said Thank You: tincho80, Whitebarn

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11 Nov 2022 04:02 #256400 by Ac1dburn
Hey, if it makes you feel any better, I'm also tying to get a solid tune on these servos, or at least the ISV57T's. My biggest problem with the documentation/ software, is that they call all the parameters terms that aren't used in servo tuning guides elsewhere, which makes it hard to know for sure what setting/ parameter is really what. I also looked at that guys videos, but I still don't know how the stepper online software's tuning graph works. It's nothing like his. Sorry I'm not much help, but I'm on a mission to really learn these motors and I'll report back if I figure anything out.

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09 Jan 2023 00:43 - 09 Jan 2023 00:47 #261313 by tincho80
@PCW: The problem was not the limiting speed. its was more like the "the slower I moved the axis" the worse the offset got, the faster I moved the axis moved, the closer they were to their theoretical position.
It is solved now. thank to "EragonPower"'s post. the manufacturers steptime were wrong. 3000ns does the deal.
but many thanks anyway!!!
Last edit: 09 Jan 2023 00:47 by tincho80.

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09 Jan 2023 01:21 #261318 by tincho80

DIRSETUP   = 3000DIRHOLD    = 3000
STEPLEN    = 3000
STEPSPACE  = 3000

thank you very much! that was the solution to my problem! the manufacturer's params (2500ns) were wrong! It just wasn't working, not even when the motor-shafts could spin freely, without being attached to any other parts...
and please excuse the late reply! I didn't check the box for email notification. now I will..

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