Messages

101

General Mach Discussion / Re: spindle load feedback to mach3

« on: July 18, 2013, 09:07:52 PM »

Putting a voltmeter on the VFD will tell you nothing of value.  You need to be looking at current, which means putting an ammeter *in series* with one phase of the motor.  The Tormach load meter is nothing but an analog ammeter.  An analog ammeter contains a shunt, which is a very small, precisely known resistance.  When current passes through it, it creates a small voltage drop (typically 50mV at maximum allowed current), and the meter itself is a very sensitive voltmeter, connected across the shunt, that reads full-scale with 50mV across it.  Look at digikey, mouser, and other electroincs supply houses, and find one with a suitable full-scale reading.  But, a good analog ammeter will not be cheap.  However, a digital meter, in this application, would be completely useless.

Regards,
Ray L.

102

General Mach Discussion / Re: spindle load feedback to mach3

« on: July 18, 2013, 07:48:39 PM »

The VFD may well be sending raw, instantaneous current readings.  If so, the readings you receive will not be steady, but will have quite a bit of variation from one reading to the next, and their values may well exceed 100% load at times, as most VFDs allow short-term overloads of as much as 200%.  To make them usable, it may be necessary to filter them using a digital filter, which is a software algorithm that that performs exactly the same function as an analog filter (resistors and capacitors), but all the processing is done on digital values, rather than analog voltages.

If I were doing it, Id make use of the current limit feature that is almost certainly built into the VFD, and take the VFD ERROR signal, and run that into Mach.  Then, when you over-load the machine the VFD will shut down, and you will simultaneously get an ERROR signal from the VFD you can use to shut down Mach3.  I think you'd find that would work much more reliably, with much less tweaking and tuning.

Regards,
Ray L.

103

General Mach Discussion / Re: spindle load feedback to mach3

« on: July 18, 2013, 05:13:52 PM »

You'd have to do a lot more than just read load to do that reliably, as you WILL see momentary loads that go well over 100% (for instance, when you enter a corner), and you don't want to trip on those.  Plus, the readings you get will typically be VERY noisy.  At a minimum, you'd need to do considerable digital filtering, just to get something stable enough to work with.  I don't see how you'd do that in a brain.  Possibly a macro-pump.

Regards,
Ray L.

104

General Mach Discussion / Re: spindle load feedback to mach3

« on: July 18, 2013, 11:19:08 AM »

I'm curious what you plan to do with spindle load feedback.  Mach3 can't really make use of it to do much useful, other than display it.  An analog ammeter connected to the motor would seem a more useful tool to me....

Regards,
Ray L.

105

General Mach Discussion / Re: Uncommanded Z motion.

« on: July 15, 2013, 03:30:40 PM »

I am not the same person.  I followed the link you posted, and although my problem is similar, it is not the exact same.  My runaway condition only occurs with the Z going positive (thank God!), and only with the Tormach Pendant (although I have never really used the keyboard for jogging).  I played with the keyboard a bunch to try and get it to occur with it, but I could not.

Could still be related, as both involve motion continuing after, in theory, it should have been commanded to stop.  You're using the ShuttlePro plug-in, which could easily make it behave slightly differently.

Regards,
Ray L.

106

General Mach Discussion / Re: Uncommanded Z motion.

« on: July 14, 2013, 07:23:03 PM »

I'm assuming you're the same guy who posted a similar problem on CNCZone?  Here is the thread I referenced that sounds like the same problem:

http://www.machsupport.com/forum/index.php/topic,24912.0.html

Regards,
Ray L.

107

Third party software and hardware support forums. / Re: whats best 3axis for $5000

« on: July 14, 2013, 03:03:21 PM »

That's kinda like asking "What's the best motor vehicle for $5000?".  Do you need a car?  Truck?  Motorcycle? RV?  Boat?  Does it need to haul cargo, or people?

What kinds of things do you expect to make?  How big are they?  What metals will they be made from?  Aluminum, steel, stainless, titanium are all have very different requirements.  Do you need coolant?  What size tools do you need to use?  Smaller tools require much higher spindle speed.  Larger tools require much more spindle torque.  What total work envelope do you require, taking into account vises, clamps, fixtures,, etc.  What kind of accuracy do you require?  What's more important - accuracy or speed?  Does that $5000 include all the necessary tooling, which typically costs nearly as much as the machine itself, sometimes more?  All these things and many, many more have to be factored into deciding what the "best" machine is for any particular application.

Regards,
Ray L.

108

General Mach Discussion / Re: using variables

« on: July 12, 2013, 08:57:43 PM »

In theory, you should be able to use a variable anywhere you'd normally use a literal number.  Given how idiosynchratic the Mach3 parser is at times, I have no idea if that is really true for Mach3, but I'd guess it is.

Regards,
Ray L.

109

General Mach Discussion / Re: Flatten my G-code

« on: July 09, 2013, 07:23:53 PM »

Terry,

He's asking for the code itself to be displayed "flattened" - all parameters resolved to numeric values, all subroutines "un-rolled" into in-line code, etc.  One of your parametric programs would end up being 100,000 lines long!

Regards,
Ray L.

110

General Mach Discussion / Re: Kernel speed set to high on z axis and will not save calibration.

« on: July 09, 2013, 09:36:18 AM »

If you're only setting the steps per to 9387, why on earth do you WANT to set the kernel speed above 25K?  There is absolutely no benefit whatsoever to doing so....

Regards,
Ray L.