Need Help!- Stepper motor high frequency noise!

[speedydumpster]

Hey guys,
I'm getting a squeel when I turn on the machine power (hitting F1) in EMC2. Here is the process that I am using.
1. I turn the computer on.
2. Turn on the controller box. The steppers go rigid at this point.
3. Open up EMC2. No noise is present at this time.
4. Toggle the machine power on in EMC2. High pitched frequency noise starts.

I turned the controller off and then unplugged the Y and the Z motors - the high frequency whine still occurs. Then I tried a replacing the X axis motor with the Y axis motor and the noise still occurred. Then I tried putting the X axis motor on the Y axis cable, and the noise still occurred. I was just trying to rule out a bad cable or a bad motor. I then checked the resistance on all the poles of the motors and they are all the same. I can run programs and the motors will move. This machine is a old Light Machines Spectra 0200 mill/controller.

This drives me insane and is pretty loud.
Does anyone have any suggestions.

[marzetti]

What drives are you using?

[speedydumpster]

Thank you for the reply. I am using the light machines controller box. I created an adapter cable like the one that you see here.
Adapter Cable [MeshCMS]
I just don't know if it will work. It's squeeling really bad, my little brother thinks it might be a charge pump, and my dad said that it's probably because EMC2 is PWM'ing in the audible frequency range, which is causing the noise. I'm not an electrical engineer, and this is my first experience with this stuff.
Thanks,
Dave

[chester88]

I would check your wiring and the pinout in stepconf.
Are you using a charge pump?
When you say the motor moves does it move the right distance?
Very strange!

[FatFreddie]

I get this with my cheap drivers, the expensive ones are near silent (the motors, cabling and EMC2 setup are identical). It varies in character and volume according to where the motors stop (I assume where it is in the microstepping cycle is the determining factor). I think your dad is probably right about the cause.

[speedydumpster]

I believe I figured out the problem. I think I had a bad cable. I re-wired the cable that went to the control box and it's quiet now. Thanks for the input guys!
Take care,
Dave

[photomankc]

That's cool but that is something I get all the time with the Keling 6050 drivers and it happens on every motor on every cable. It really depends on where the motors are when they stop. It's the chopper circuit in the drivers that causes the noise and dad was right, it's in the upper audible range as I understand it. Generally it quits as soon as I step in any direction by any amount. Not enough of a deal to get in a twist over to me but yeah it can get rather distracting when it's loud. I don't always get it but usually I do.

I didn't think much of it because when I was playing around building my own drives they always did the same thing when they powered up after a disable, or power-off so I was used to hearing it.