noise?

Hi there!

I just upgraded an old CNC whith some leadshine stuff (CS-D508 drivers + CS-M22323 motors) but some weird noises appeared on my X and Y axis.
For me it sounds like a mechanical problem like bad rail alignement, rust or so but here is the thing:
when I set the motors to open-loop, the noise mostly disappears :confused:
The machine is very old (30 years or so... lol) and there are some few signs of wear and she's a little rusty, but overall, she's still looks great.
I also cleaned and greased everything but it didn't changed anything.
This open-loop thing really confuses me, maybe the problem comes from my motor driver settings?

Here is a video whith motor set to closed-loop:
https://drive.google.com/file/d/14gN...ew?usp=sharing

Open-loop:
https://drive.google.com/file/d/14d-...ew?usp=sharing


Some help would be great!

Sounds like resonance. Maybe a setting.

Thanks for the answer! Somehow I missed it, so sorry for the delay...

I'm pretty new to all this CNC stuff, I already tried to tweak some of the settings, but I really don't know which one(s) could cause the noise, and some settings I don't even undestand what they mean, and therefore I didn't touch them (don't want to break anything or just rely on luck...).
Here is the full list of settings:
- Microstep Resolution (1600)
- Peak Current (6Amps)
- Closed-loop Holding Current Percentage (50%)
- Encoder Resolution (4000)
- Allowed Max Position Following Error Pulses (4000)
- Open Loop Output Current Percentage (50%)
- Distance to send "In Position" Output Signal (8)
- Allow clearance of Position Following Error (yes)
- Current Loop Bandwith (1500)
- Current Loop Ki (300)
- Position Loop Kp (25)
- Velocity Loop Kp (25)
- Velocity Loop Ki (0)
- Motor Shaft Locking Time (200)
- Internal Filtering Time (15)
- Soft-Starting Time (1)
- Auto-tuning at Power-on (yes)
- Velocity Switching Point: Open Loop to Closed Loop (18)
- Velocity Switching Point: Closed Loop to Open Loop (18)
- Motion Type (Normal)
- Self-Test at Power-on (No)

Just in case, here is the manual (go to p14): http://www.leadshine.com/UploadFile/...nerCS_sm31.pdf

I'm sorry, I know this is not very fun, but I just can't solve this by myself.

Like you, I really don't know exactly what effect these parameters would have on the operation until I tried adjusting them. I guess I would start by playing with these parameters, one at a time and note the result. Most likely setting them lower with the exception of the ones in bold text that I might set higher.

The Kp and Ki control the ''stiffness'' of the system. Higher means stiffer and more subject to oscillation.

- Current Loop Bandwith (1500)
- Current Loop Ki (300)
- Position Loop Kp (25)
- Velocity Loop Kp (25)
- Velocity Loop Ki (0)
- Motor Shaft Locking Time (200)
- Internal Filtering Time (15)


Many times if a small change doesn't seem to have an effect, then try a large change.

Worst case you can always set them back to the original settings if the changes don't produce the desired result. It is very unlikely that you would actually break anything.

...I see there is something from Leadshine for tuning that may help ya.
http://www.leadshine.com/UploadFile/...s_20131207.pdf

ProTuner manual link
http://www.leadshine.com/UploadFile/...nerCS_sm31.pdf

good luck on your adventure,
DJ

Quote:

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Originally Posted by Janosch89

Hi there!

I just upgraded an old CNC whith some leadshine stuff (CS-D508 drivers + CS-M22323 motors) but some weird noises appeared on my X and Y axis.
For me it sounds like a mechanical problem like bad rail alignement, rust or so but here is the thing:
when I set the motors to open-loop, the noise mostly disappears :confused:
The machine is very old (30 years or so... lol) and there are some few signs of wear and she's a little rusty, but overall, she's still looks great.
I also cleaned and greased everything but it didn't changed anything.
This open-loop thing really confuses me, maybe the problem comes from my motor driver settings?

Here is a video whith motor set to closed-loop:
https://drive.google.com/file/d/14gN...ew?usp=sharing

Open-loop:
https://drive.google.com/file/d/14d-...ew?usp=sharing


Some help would be great!

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If set the motors to open-loop, the noise mostly disappears, then the problem should not come from the mechanical parts.

Thanks all for the replies!

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...I see there is something from Leadshine for tuning that may help ya.

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I think you misunderstood my problem? Pro-Tuner is working fine for me!

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If set the motors to open-loop, the noise mostly disappears, then the problem should not come from the mechanical parts.

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Yeah, that's what I'm thinking too. I'll try to tweak the settings then...
Thx Jim for your newbie-friendly reply, as soon as I can, I'll give it a try!

Quote:

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Originally Posted by Janosch89

Thanks all for the replies!
I think you misunderstood my problem? Pro-Tuner is working fine for me!
Yeah, that's what I'm thinking too. I'll try to tweak the settings then...
Thx Jim for your newbie-friendly reply, as soon as I can, I'll give it a try!

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Prob dumb questions but,
Do you definately have the closed loop wiring in the correct order? .No n/g mixed up or other issues.
How is your cable shielding on all your signal wires?
Is vfd fully shielded and filtered?
How many ancilliaries do you have running off the same voltage power supply, or are you using different voltages for different circuits?

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Do you definately have the closed loop wiring in the correct order?

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I'll check it, but the wiring is pretty self-forward (leadshine's manual is very clear),
so I don't think I messed it up (on 2 motors furthermore), but I'll check it!

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How is your cable shielding on all your signal wires?

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Encoders are twisted pairs inside a shielded cable, shield is grounded on the driver side (to the ground of my power supplies). So are step and direction wires (but not in pairs). Is that ok?

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Is vfd fully shielded and filtered?

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No VFD for now :'(

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How many ancilliaries do you have running off the same voltage power supply, or are you using different voltages for different circuits?

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The 3 drivers are powered by a 48V supply (a meanwell RSP-750-48) , controller is an AXBB-E (from UCCNC), powered by a 24V (meanwell RSP-320-24) and a 5V (meanwell LRS-75-5) power Supply.

I have not much time this week, I'll look at it next week. I'll keep you updated, thx again!

Did you connect to the ProTuner software and tune the drive before or after you noticed the noise?

I would suggest that you reset all the settings to the factory defaults and test from there. Those settings will work fine in 90+% of all cases and most inexperienced users make the motors run worse, not better.

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Did you connect to the ProTuner software and tune the drive before or after you noticed the noise?

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I don't remember exactly, but I think I first tried to move the axis before connecting proTuner, and then tried to tweak things, because of the noise. I tried to activate auto-tuning, change current but it's when I switched to open-loop when the noise went away... I have to try other settings like Jim suggested, I didn't tried it because the manual pretty much wants you to leave all to default I think, and also, I don't get why switching to open-loop makes the noise go away!

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I would suggest that you reset all the settings to the factory defaults and test from there.

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Machine is screaming even with default settings but yeah, I'll go from there!

Ok, I finally found some time!

You guys were completely right: the problem was related to my settings: I changed the
velocity loop Kp from 25 to 10, and the noise disappeared!
Thank you all for your help, this made my day!