[CohaganEng]

We recently purchased a Novakon NM-200 Series 2 CNC Mill running Mach 3. The mill ran perfectly for about one month, then last week I was making a small fixture using MDI, I drilled one .250" hole in some 6061-T6 and moved to the next hole, typed S1200 M03 and hit enter, the spindle raced up to a very high rpm (something over 6000rpm) and then stopped working. We then started inspecting the machine for damage and noticed the VFD blew off 3 capacitors.
Since the machine is only 6 weeks old and still under warranty Novakon sent us a new VFD, We then installed it and ran the Spindle Calibration program and saved the new curve. Now when you turn on the spindle in MDI, S500 M03, The spindle races up to a high but unknown RPM, my Machinist ears tell me it is around 6000 rpm or so but the Machine states 500RPM. During the spindle calibration the spindle responded perfectly all the way to it's 6000rpm max.

What could be the issue? Any help will be greatfully appreciated.

Thanks
Brent

[JoeBean]

Weird. How does it respond to m4? Can you post a screen capture of your spindle setup page? What happens if you do, for example, s1000 followed by s200? Do you have spindle override set high? Though that should only be able to go to 250% tops...
I assume it does the same thing with loaded gcode too right? As in not just through mdi?
If it weren't for the fact it works in setup I'd think it's your BOB. Do you have any other software running? Maybe something new installed? I know running VisualCAM when Mach's running can cause all sorts of odd behaviour, for example, as it's looking for a dongle on the parallel port.
You might want to try asking on machsupport.com/forum too, as it seems it might be Mach specific.

Oh, thinking off the top of my head, I don't suppose you have min spindle speed set too high?

[CohaganEng]

Thanks for the response. The spindle responds the same way both M03 and M04, MDI or in program. I can't get a screenshot as there is the picture software on the computer, it is a dedicated system only running the Mach 3. The parameters are set from Novakon and have not been changed. I could list them if you think it would help. What is a BOB?

I have posted on the Mach3 Forum and contacted Novakon, no help...Very disappointed in there tech support.

Thanks Again,
Brent

[JoeBean]

Hi,
Sorry, BOB = Break Out Board, the board that the parallel port connects to. If there's something going wrong so the signal is being messed with at the board it can cause speed issues, but it should be all the time, ie. it should have been happening when you were setting it up.

I had to redo the settings for mine when I got it. The file was wrong on a number of issues, so I wouldn't guarantee that it's ok just because it came from Novakon, although understand mine was AFAIK the first unit sold, so they likely weren't using the same files then.

So first off, before going any further, try m3 s300 and immediately m5 to stop (or estop). What's shown on your screen where it says s-ov under spindle speed? If it's not 300 that's your problem - spindle speed override. Otherwise...

Let's assume your setup is like mine... Backup (ie. copy the, somewhere) all your files under c:\mach3 before proceding, just to be safe...
Under config, ports&pins, spindle setup what's the minimum pwm %? Try 10. What's your PWM Base Freq? Try 1000. Make sure Use Pindle Motor Output is checked, as is PWM Control, first or you won't be able to change settings. Set 1 second up and down delays. Immediate relay off checked. I also assume modbus spindle & special functions & options are disabled, correct? Under Port Setup and Axis... tab I have kernel freq set to 35000. Under Motor Outputs my Spindle is checked, step pin 14, Step low active checked, step port 1 dir port 1.

Under config, pulley spindles ensure pulley 1's min speed is, say, 300rpm. Go to the settings page (alt6) and make sure pulley 1 is selected.

Did that help?
Do you have an oscilloscope or a meter capable of reading/recording duty cycle? You could use that to see what's being sent to the BOB, and from the BOB to the motor.

If that doesn't work I also uploaded my xml to here. Rename it, copy it to your Mach3 folder, run the Mach3 application in that folder, select the xml name you just copied, and try that.

Hope that Helps!

[CohaganEng]

Joe,

The Spindle speed override checks o.k.

All my setting are the same as yours except my PWM base is 1400 and my Min PWM setting is 5%. I changed them to match yours exactly and the problem still persists.

The pulley spindle settings check OK also.

This time I just tried it, S300 M03 and the rpm races up still but now it says"
PWM Bumped to the minimum setting"

I will have to call in a guy to have it 'scoped.

Thanks
Brent

[JoeBean]

The overide is because the minimum speed is calculated bynthat 10%.

The xml file could still be corrupt, as it's quite common with mach3, so if you haven't already download try my xml. It really sounds like a mach problem given that it's spinning at the right speed during setup.

[CohaganEng]

How do I save my current XML and load your XML?

[CohaganEng]

Oh, I didn't notice that the XML procedure was in the manual. Shows how much I read things.

[CohaganEng]

When I load your XML file in Mach3 all I see is the upper tool bar and a blank white screen.

[JoeBean]

Just make sure you give it a name different than the profile you're using (so it doesn't overwrite your file). And back the directory up first by copying it somewhere else, as mentioned before.

If this doesn't fix it I'd try restarting in safe mode ans running it, see if that works (restart mainly to stop any unnecessary programs from running). I've never tried running in safe mode but it should work.

If that doesn't do it then I'd bet on some hardware issue between the computer and the motor, because AFAIK every setting that could cause this problem should be in the xml, and the onky other software issue I can think of would be some other program wrenching control of the parallel port away from Mach, which I can't see happening now but not during setup, and should be negated by a safemode startup. Checking signals with a scope would be your logical next move.

[JoeBean]

When I load your XML file in Mach3 all I see is the upper tool bar and a blank white screen.

Sorry, you replied while I was replying. It's likelyndue to you not having my screenset. Go View, Load Screens, 1024.set is the default so select it (it's in the mach3 folder)

[CohaganEng]

Joe,

I loaded your XML and the 1024 set. Homed the machine, and the problem is still there.

So I guess it is hardware?

Thanks
Brent

[JoeBean]

Joe,

I loaded your XML and the 1024 set. Homed the machine, and the problem is still there.

So I guess it is hardware?

Thanks
Brent

Sounds like it, unfortunately. Some people have had problems with the parallel port on the computer. But it could also be the BOB or motor controller (even though you just replaced it) or cabling. Checking the pwm signals should give you a clue which way to look. You might get some indication of the frequency of the control by just probing voltage with a multimeter. At, for example, 50% duty/PWM you should get around 2.5V (50% of 5V) but it won't be particularly accurate. Pin 14 is the parallel port and BOB pin in question, remember that we're active low so 0v =100% cycled to gnd = top speed.

IIRC your BOB should be this one. Lots of useful info there on it's function & wiring.

One other thing to check, see this thread post 50. He's from the spindle & bldc controller manufacturer that supplies the spindle on the nm-200s2 (he's usually quite helpful, too). Note the jumper used for 110V. IIRC ours is supplied with 220V, so that jumper should be disconnected.

[CohaganEng]

Joe,

Thanks for all the help, I really appreciate it.

Brent

[JoeBean]

No prob. Take care!