Topics

1

General Mach Discussion / Spindle calibration problems

« on: November 13, 2013, 08:45:52 PM »

I can't seem to get the spindle calibration function to work correctly.  When I start the spindle it starts fine but then when I click Autocal it immediately stops the spindle and says "Autocal terminated, spindle stopped".  Trying to do the autocal without the spindle running just asks me to start it at any speed.  I'm trying to get an accurate actual speed to commanded speed relationship but right now it is pretty far off.  For example, S200 gives me 300rpm, S1000 gives me 930rpm, S4000 gives me 5140rpm.  I've plotted the curve every 200rpm and it is not linear (especially around the base frequency of the motor at 1800rpm).

My spindle motor is an inverter duty AC motor with VFD.  I'm using a ethernet smoothstepper.  The motor also has an encoder that I have run the Z channel to the ESS to give me a 1ppr index pulse and this is working fine.  The displayed RPM in Mach is exactly the actual rpm confirmed with a laser tach.  The pulley is a 1:1 ratio and I would like to accurately go from 200rpm to 5000rpm.  Oh and the VFD frequency is controlled with a C41 card which converts the PWM to a 0-10v analog signal.

Can anyone walk me through the set up and procedure for this and tell me why it isn't working?  I've broken my brain trying to figure it out and am feeling a bit lost and burned out.

Thanks for the help.

2

SmoothStepper USB / Spindle encoder and ESS with Mach3

« on: October 04, 2013, 01:38:48 PM »

I have an ESS and 1024ppr differential encoder that has channels A, -A, B, -B, Z, -Z and I want to get it communicating with Mach.  I originally was just going to use the Z index channel and run it through the ESS but after some reading it seems that it may be possible to use the actual 1024ppr channels for better speed accuracy.  The main reason I want mach to know the RPM is so I can calibrate the spindle speed because the rpm/hz linearity is borderline acceptable but I would also like the capabilities of more accurate threading or rigid tapping (perhaps in the future).

Is this possible and how do I go about doing it?  Should I just stick with the Z channel?

3

Third party software and hardware support forums. / Need help with c41 board and pwm spindle control with VFD

« on: July 31, 2013, 09:39:44 AM »

Problem #1
I am replacing the BLDC driver and motor on my mill with a Durapulse VFD.  The Durapulse VFD uses a 0-10v analog signal input for spindle RPM.  The proprietary hardware electronics of the mill outputs a PWM signal so I have a C41 board (rev.1) from CNC4PC to convert the PWM signal to an analog voltage signal for the VFD.  Sound simple right?  Well the problem is that the PWM signal from the machine is inverted, meaning 0% duty cycle is max RPM and 100% duty cycle is min RPM or an active low configuration.  This is the way the supplied BLDC driver needs the signal.  The Mach3 interface has the same configuration to make it compatible.  I can change the Mach3 step setting to active high but I can't change the hardware of the machine so it will always output an active low signal.  The C41 board however only reads active high.

I think I need to put a circuit in between the Mill hardware that is outputting the backwards PWM signal and the C41 board to make it work.  The question is how do I invert the PWM signal, I think it should be easy to do but really don't know where to begin.  I'm assuming I have to make some type of op amp circuit.  Please help or offer suggestions.

Problem #2
Even when supplying the correct active high PWM signal directly from Mach3 to the C41 card I get no dynamic response on the output analog voltage.  There is just a constant ~1.3v which I can adjust slightly with the pot.  No matter what the input signal is to the c41 I can't get the output voltage to change or even get close to 10v.  Perhaps it's wired wrong?  I am supplying the external power with +12VDC and -12VDC for ground (I'm not sure if that is the correct way to do it).  I don't have the relays wired yet, I'm just trying to get an analog output voltage first.  Please tell me what I'm doing wrong.

Here is how it's wired:


Also here are some relevant images of the VFD terminals:


I'm banging my head against a wall trying to figure this out.

 

4

General Mach Discussion / Having a few issues with Mach

« on: March 26, 2011, 12:56:08 AM »

Here are a few of them.  If you can help me solve any of these please help, I'm a little lost.


1. When jogging, the axes continue to move for anywhere up 3 sec or so after I release the key. A few days ago this was not happening the axes stopped on a dime as soon as I released the keyboard key. Also the DRO does not change while the axes are moving anymore, they only update after the axes stop moving which did not happen before.

2. Sometimes the axes stutter and freak out making all sorts of noise (and losing steps) when doing simple moves. I can jog around at 75IPM and it's smooth, then I do a G0 move (also at 75IPM) in the MDI and BWAAAGGGAGAGHHHAGH. I have a macro which sends the Z to a tool change position and it always does that even if it is an G1 F10.

3. Somehow something has changed where when I reference all home the X axis no longer does anything the light just flips to green without the table even moving. I didn't change anything to do that that I can tell.


I can post my .XMLs if that would help

5

General Mach Discussion / Problem with Error Involving Arcs

« on: March 23, 2011, 12:28:07 AM »

Hello.
I keep getting errors in the arc lines that my CAM software spits out and I'm not sure how to fix the post processor or Mach itself to get them to work. 

Here are the details:

CAM software is RhinoCAM using Mach3-Inch.spm post processor

In the circle tab I have the following options

Output Format
-I,J,K and Radius
-I,J,K only             <-----------this one is selected
-Radius only

Arc Center (I,J,K)
-Absolute         <----------------this one is selected
-Vector from Center to Start
-Vector from Start to Center
-Unsigned Vector from Start to Center

Here is the circle block format:
[CIR_PLANE]
[G_CODE][NEXT_X][NEXT_Y][NEXT_Z][NEXT_I][NEXT_J]

RhinoCAM also has the following options that can be checked:

-Output arcs as linear segments                   <-------------I have this one unchecked but I'm not sure what I should do with the other two.
-Output spiral motions as linear segments
-Output helix motions as linear segments


Now in Mach I tried both absolute and incremental  but I keep getting these two errors:



In IJ mode Absolute I get this error:

Zero radius arcLine 140

140:G03X-1.1733Y0.5598I-0.8561J0.9783



In IJ mode Incremetal I get this error:

Radius to end of arc differs from radius to startLine 942

942:G02X1.6663Y0.4917I0.3265J0.4175


These are just the first ones to pop up in reality almost every arc line gets an error.

Sorry can someone help me get this straightened out?

I would much rather cut arcs than line segments.
 

 

6

General Mach Discussion / Help with tool changes

« on: March 21, 2011, 01:39:21 AM »

Hello,
I'm a new Mach user so I don't know much but I'm in the process of customizing some things and I don't know how to do it.

Here is what I want to happen:

When Mach encounters an M06 for tool change I want the Z to move up to either the home switch/limit switch/or a predefined machine coordinate high in the Z but I want X and Y to not change.  I would also like a pop up window to display a message with the details of the requested tool (i.e. "Please load tool #3 .5 flat endmill", or "Please load tool #4 3.15 45deg facemill", etc.) and possibly even a photo image of it and a beep or a .wav saying "please load new tool" or something.  I would also like to put a "go to tool change location" button on the program screen that executes this action.


As an aside, how do you control tool #0?  I would like to use T0 for the indicator reference tool but I can't figure out how to use the T0 so I have it as T1.

Thanks for the help