Author Topic: Spindle problem... slowly decreases RPM until stop.  (Read 4778 times)

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Offline guido666

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #20 on: February 27, 2015, 12:54:03 AM »
It's a USB SmoothStepper, but yes, I could probably get another computer into the garage tomorrow and try it.

Offline BR549

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #21 on: February 27, 2015, 08:49:20 AM »
IF it is a SMOOTHSTEPPER then forget the spare PC as the SS does all the PMW ouput work not the PC.  Just check the output from the SS.

(;-) TP

Offline geh7552

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #22 on: February 27, 2015, 10:40:30 AM »
Does the SS have it's own +5 volt power supply or is it using the USB port power. The USB port may not be capable of powering the SS. There are a few postings about the PC's USB port +5v power problems with USB SS.

I have a Ethernet SS with a Gecko 540 controlling a VFD (0-10V) without issues. However, the ESS has it's own +5v supply.

Offline guido666

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #23 on: February 28, 2015, 07:07:39 PM »
The SS does not have it's own power supply.

I plugged it into another computer, this time a desktop instead of the regular laptop, and used the same Mach3 .XML profile.  The same thing happened, and is oddly still affected by the spindle's acceleration setting.

I also tried both the .24 and .30 USB drivers, and the 17F and 17FE Mach3 plugins.  Same results.

Offline BR549

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #24 on: February 28, 2015, 08:46:38 PM »
I dought that this is a sotware problem it is very much like a hardware problem Sagging power. Using a SS it was not usefull to swap PCS as the PC does not control the PMW to the Spindle controller the SS does.  DID you check the incoming voltage to the SS. You have very limited power from the PC's USB port. Try supplying power to the SS with an outside power supply.

Have you talked to Greg over at Warp9 to see what he thought ?

(;-)TP

Offline guido666

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #25 on: February 28, 2015, 09:50:21 PM »
I emailed Greg, and he responded that he wouldn't be able to respond until Wednesday (4 days ago), and I haven't gotten a response to any of my emails after that.  I'm hoping he'll have something insightful, once he gets a chance to respond.

Offline guido666

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #26 on: March 01, 2015, 05:27:38 PM »
An external 5V power supply didn't change anything.

I did flip the Active Low for the spindle step pin back off, because speed was operating in reverse (higher setting got slower speeds).  I can get constant spindle RPM now, but it's way off "specified" value.

Some questions...

1.  When I set the speed to 2500, Mach3 fills in the "S-ov" field to 2500, and RPM gets something value that winds up to about 95%, such as 2377.  See attached picture.  What does "S-ov" mean?  Is this RPM value being off normal?  I have a pulley ratio of 1, so shouldn't it just be 2500?  Why does the RPM value ramp up, then stabilize?

2.  I checked everything, and the spindle is providing 5.01V, and getting back 3.58-3.70V at 2500 (of 2800 MAX) RPM.  This happens repeatably regardless of which of the two computers I hook to, and whether I use USB 5V or external 5V.  So it seems like it's happening on purpose.

Offline guido666

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Re: Spindle problem... slowly decreases RPM until stop.
« Reply #27 on: March 01, 2015, 05:39:06 PM »
Also, can someone explain the spindle motor tuning settings, as they pertain to PWM spindles, better?  The Mach3 manual does not provide very thorough explanations, and I'm pretty lost.

1.  Steps Per:  What does this do?  (I know what it does for a stepper, but how about here?)  I've tried settings from 100 to 20,000, and all it seems to do is change how fast the spindle speeds up.  Smaller settings result in smaller speedup, so 200 takes like 2 minutes, and 10000 takes like 10 sec.  Does this have an effect on the problem posted above, where RPM never reaches the speed I set, or the voltage being less than max at full speed for the pulley?

2.  Velocity:  What does this mean for a spindle?  Does it affect maximum speed?  Nothing I change in here seems to affect anything obvious.  Also, sometimes Mach3 forcibly sets it to something I can't change, I'm guessing based on my Steps Per and Acceleration values.

3.  Acceleration:  What do I want to put here?  Obviously bigger numbers seem to result in faster acceleration, but how do I computer/know what it should be?  Is it related to Steps Per and/or Velocity?

4.  Step Pulse / Dir Pulse:  Do settings here have any effect on PWM spindles?  Changing them doesn't seem to have any effect.