Messages

1531

General Mach Discussion / Re: Continuing a job after an event stops it

« on: October 11, 2008, 09:00:14 PM »

Spend the time to get good at re-zeroing the machine - You'll be doing this a lot for a while.  It's a good idea to always have some repeatable reference position on each part or fixture.  it can be as simple as a single hole, or a couple of edges you can reference to.  If you have home switches, just zero to your reference when you setup the part, and save the offsets as a fixture offset, and you can then quickly go back to it after an oopsie.

Once you've buggered the program, it's a good idea to back up the program to some good starting point.  I usually just back up to the start of the failed operation.  It's also a good idea to do an "air cut" just to make sure you've really got things back under control.  It's up to you to remember to turn the spindle and coolant back on if you either turned them off manually, or they were shutoff by a stop or E-stop.

Regards,
Ray L.

1532

General Mach Discussion / Re: Macros For Dummies

« on: October 11, 2008, 03:42:00 PM »

Graham,

    I seem to be missing something here....  I have the Macro Pump enabled.  I wrote a script that does something inane when the "Machine Coords" LED is lit.  It works fine if I execute from the script editor, but nothing otherwise.  So, I then edited the "Ref All Home" button script.  I made my changes, saved it.  But it never seems to execute - clicking the button seems to do nothing.
    How do I make a macro function that is invoked when and on-screen button is pressed?  How about when a PP input signal changes state?

Regards,
Ray L.

1533

General Mach Discussion / Re: Macros For Dummies

« on: October 11, 2008, 02:37:15 PM »

Graham,
  Will macros be auto-loaded on start-up, or do they have to be explicitly loaded?
  Also, am I correct in thinking macros run in a separate thread, so we need to be "thread-friendly"?  What I want to do is poll some inputs that correspond to pendant buttons, so I assume the correct way to do that is to request the state of those inputs, take any required action, then do a sleep(100)?  Is there a better way to do this?  Is there any event notrification mechanism (i.e. - when this event (input signal changes state), call this macro function).

Regards,
Ray L.

1534

General Mach Discussion / Re: Macros For Dummies

« on: October 11, 2008, 02:24:23 PM »

Graham,

  Do I save the Macro to a specific place, like the macros/Mach3Mill directory?

Regards,
Ray L.

1535

General Mach Discussion / Macros For Dummies

« on: October 11, 2008, 11:10:42 AM »

How do I create a macro?  I currently use (well, used to use....) brains for the I/F to my crappy pendant.  Since that is no longer working right with SmoothStepper, I want to translate it to a macro instead.  Writing the code is, I think, trivial, but where do I then put it/what else do I have to do to "integrate" it into Mach?

Regards,
Ray L.

1536

General Mach Discussion / Re: VFD Forward/Reverse Relay Control in Mach3

« on: October 11, 2008, 10:24:02 AM »

Chris,
    I could be wrong, but I don't believe the C23 supports PWM for the spindle.  It expects a STEP single, and it does a frequency to voltage conversion on that, just like all the other CNC4PC boards.
   I also believe Mach has a FWD output, and a REV output, so you'll need to wire two relays, so that the one activated on M3 only activates the START intput to the VFD, while the one activated on M4 activates both the START and REV inputs to the VFD.  However, I'd check the VFD documentation very carefully.  They often have configuration options that define how those inputs work, so they can be configured as START+REV, or separate FWD/REV inputs.  The latter is more compatible with the way Mach works.

Regards,
Ray L.

1537

General Mach Discussion / Re: Configuring Mach 3 for a VFD and Spindle

« on: October 10, 2008, 08:20:49 PM »

I'm almost sorted out. Mach 3 is sending step info to the the CNC4PC C6 speed control board, and Spindle On/Off direction that triggers a relay on the C6 board. Groovy. The C6 board now converts that step input to the voltage output, and when I change speeds in Mach 3, the C6 board output changes. Woohoo!

My silly question now is about getting the VFD relay to turn the spindle on. Mach 3 outputs a spindle-on voltage of about 5V. The VFD wants 9V at least to trigger the spindle ON/ CW switch. Can I use the same 12V that powers the C6 board as the voltage to turn the spindle on? Seems logical, but because I'm not perfectly clear on isolating grounds and such, I'm not sure I can use this voltage. I suppose this is a question for the CNC4PC people, but if you know, that would be great.

This has been a great learning experience. I appreciate your patience with me here!

Wayne from White Salmon

Wayne,

    Doesn't your VFD provide the correct voltage to drive the motor on signal?  Usually there is something like a 12V power supply output that you connect to the FWD or ON input to turn it on.  On mine, I used one of the relays on my C11 BOB to do the switching.

Regards,
Ray L.

1538

General Mach Discussion / Re: My machine is not repeating

« on: October 08, 2008, 06:08:04 PM »

Hi Ray I tried moving the DIR signal wire to the Z Axis to a stepper output and we had no change.
So I tried moving the Y Axis wires (the one that works OK) to the Z Axis outputs at the BOB and moved the Y Axis wires to the Z Axis at the BOB. Now the Y Axis which is on the Z Axis outputs at the BOB still works OK.The Z Axis which is on the Y Axis outputs at the BOB still is moving .001 to the positive direction every direction change. Looking at the two test it looks to me that the problem is in my drives not picking up the DIR signal quick enough at the change of direction. I would like to thank you for your ideas and a look at this from a new direction.

Thanks Louie

Louie,

    That is very odd indeed.  What motor controllers are you using?

Regards,
Ray L.

1539

General Mach Discussion / Re: Setting up Steps per inch - Need Clarification

« on: October 08, 2008, 10:45:06 AM »

Ooops!  Those numbers should be 0.004"/FOOT, and 0.0005"/FOOT.  BTW - Nook has some REALLY nice rolled screws with 0.001"/foot lead error, for barely more money than the 0.004"/foot ones.

1540

General Mach Discussion / Re: Setting up Steps per inch - Need Clarification

« on: October 08, 2008, 10:43:45 AM »

Although 10,000 is the calculated amount, you may need to adjust the number up or down a little bit. Typically, the acme screws you're using have a tolerance of ±.009 per foot, so are rarely actually 10,000 steps per inch. Also, the steps per inch can vary along the length of the screw, so you need to check in different areas of the machine and pick a number that works best overall.

That seems to me like really bad advice.  *Every* screw, even the best ground ballscrews, have some lead error.  The only difference is the magnitude of that error.  Rolled ballscrews are typically 0.004"/inch maximum error.  Ground ballscrews can get down to 0.0005"/inch.  However, the *average* pitch should be very, very close to the spec over any reasonable distance.  If you adjust steps/unit, then you're forcing the error to be less *only* at the one place on the screw where you measured it, which means you've *increased* the error pretty much everywhere else.  Not a good idea.  The only time you should compensate by fudging steps/unit is if you have a screw that isn't really what you think it is.  For example, perhaps your "10 tpi" screw is really a 2.5mm lead metric screw, in which case you'd need to adjust steps/unit by 25/25.4 to compensate.  And if you have Acme screws, this is all a little academic anyway, since your biggest problem will be backlash, not lead accuracy.

Regards,
Ray L.