Topics

1

General Mach Discussion / Inaccurate spindle speed reading

« on: June 13, 2011, 08:30:01 PM »

I installed a hall effect sensor on the spindle pully.  At 900 RPM, I get a pulse width of approximately 300 uS.  Up to about 900 RPM the DRO reads correctly, but at any speed much above this, the readout reads erratically.  The Index Debounce is set at 2, but that made little or no improvement from when it was set at 10.  I bumped up the kernel speed (to 45khz), and that improved things (previously, the rpm reading maxed out at something over 600).  

The numbers seem to indicate that this should work up to a much higher speed.  Any thoughts as to why it does not?

I suspect that widening the pulse width would improve results, and if I don't hear of some other solution, I will install a circuit to do that.  

SK

2

General Mach Discussion / Mach Crashed - won't restart after setting kernel speed too hi

« on: June 13, 2011, 05:50:02 AM »

I guess I need to know how to change the kernel speed outside of Mach.  I don't find anything called Kernel in Mach3Mill.xml, so evidently the kernel speed setting is called something else or held in another location...

What's the trick?

Thx
Scott Kelley

3

General Mach Discussion / How can I simulate Mach output on the parallel port?

« on: May 02, 2011, 06:34:41 PM »

I would like a simple way to simulate on the parallel port, signals from Mach that would enable the charge pump and exercise one axis. 

The purpose is to have an output signal for testing that is known to be free of errors that may be caused by some kind of setup problem or other issue within Mach. 

Has anyone got anything available like this?

Thx
Scott Kelley

4

General Mach Discussion / Axis' accumulating error - need to emulate Mach3 output for testing

« on: May 02, 2011, 02:08:45 PM »

A lengthy description and discussion of this issue is posted here: http://www.cnczone.com/forums/servo_motors_drives/127477-axis_dont_return_zero_-.html#post935541

Basically, the axis' slowly gain counts and creep in the positive direction.  At this point, the remaining possible culprits seem to be the servo drive itself, and Mach3.

I would like to rule out Mach3 by simulating its output.  Is there something available that will provide the pulse train output for the charge pump, and the ability to exercise one axis?

Thx
Scott Kelley

5

General Mach Discussion / Tool holders - Tool Numbers - recommendations?

« on: November 08, 2009, 04:28:36 AM »

I have a CNC mill that uses NMTB-30 holders.  I have plenty of holders, so plan to leave cutters in place in the holders.  What I am wondering is whether there are any conventions, or just personal preferences that you may want to pass on, for a numbering system for cutters.  Or should I just number them randomly starting from #1?

Thanks,
Scott Kelley

6

General Mach Discussion / Erratic Pendant operation

« on: November 08, 2009, 02:31:58 AM »

Everything is set up and working well, except the pendant.

When I move any axis with the pendant, the movement is very erratic.  It accelerates and decelerates very fast (not in the controlled manner that it does in other instances), and it moves in "jumps" - for instance, if the increment is set to .001" and I smoothly rotate the wheel 2 turns (.200"), the axis will move that distance in multiple rapid jumps rather than in one smooth acceleration / deceleration movement.

On the other hand, using the on-screen jog controls, the axis movement is well controlled - all axis' accelerate and decelerate in a well controlled manner.

7

General Mach Discussion / Trouble getting spindle speed to work

« on: July 12, 2009, 06:58:33 AM »

I've been through all of the documentation that I can find, and cannot fully sort out the spindle speed issue. 

Right now I'm getting very strange results - sometimes get 16.66 Hz operation and sometimes less.  The highest voltage I've measured on the PWM output from my CNC4PC C11 breakout board is 2.7 volts (which corresponds to the 16.7 Hz). 

I THINK I have the pulley settings correct (Pulley 1 is set up for 420 - 4200 RPM, and I can input "S" codes within that range and not receive an error message.  However the speed only changes at the very low end of that range, and it does so in the opposite direction expected (for instance, speed will be at the minimum of 10 Hz. if I set the spindle speed for 3000 RPM, but will speed up to 16 Hz. if I set it for something like 500 RPM).

Some of the references in the manual are to (I presume) an older version of Mach, and are difficult to fully understand.  Is there a complete description of the setup for the spindle speed control somewhere?  Does anyone recognize these symptoms?

Thx
Scott Kelley

8

General Mach Discussion / Trouble getting MPG to work

« on: July 09, 2009, 05:14:30 AM »

I have a CNC4PC MPG2 pendant and C22 interface card installed.

In diagnostics mode, when pressing the enable switch and rotating the axis and resolution switches, I can see various combinations of the 7 "LEDs" illuminate to indicate the inputs from the X, Y, Z, and 4 axis', and the X1, X10, and X100 resolution switches.

I do not get any movement (Jog mode set to MPG and Jog turned ON) when rotating the wheel.

I do not see any LEDs illuminated that change with the rotation of the MPG wheel.  (I would think that 2 of the port 2 LEDs should be illuminating alternately as the wheel is turned... true?)

Jog does work with keyboard or on screen "button jog" inputs.

Any thoughts?  Ideas for further diagnosis?

Thx,
Scott Kelley

9

Mach Screens / What do I need for touch screen interface?

« on: July 30, 2008, 04:22:39 PM »

I am putting together a system to run a milling machine.  I like the idea of touch-screen control, in that it would seem to make the whole thing easier (less mechanical controls to implement).  Couple questions:

Do I need to look for anything specific in the touch-screen itself, or will any brand / model work?

Is there a suitable touchscreen "driver" available for 3, possibly 4 axis mill, or would I need to create something?  (I am trying to make this as simple as possible)

Anything specific that I should know before committing to using a touch screen.

Thx
Scott Kelley

10

General Mach Discussion / Hardware suggestions?

« on: July 27, 2008, 04:41:30 AM »

Is there a sticky post or FAQ or something of the sort that describes the various pieces of hardware necessary to create a working cnc system using Mach ?  I want to retrofit a mill for 3 or 4 axis machining.

Thx
Scott Kelley