Messages

1401

General Mach Discussion / Re: Optical Limit Switches

« on: January 12, 2009, 11:02:02 AM »

Slim,

For best noise immunity, you should wire them all separately.  For safety, the limits should be directly controlling a relay that cuts power to the axis drives, and NOT depending on Mach3 to be doing that for you, as Mach3 may have lost its mind, and be the cause of the problem.  That means having a small board with logic that combines all the switched into a single relay control signal.  I'm in the process of building optical limits for my knee mill, and making a PCB to interface the optos to the BOB, and provide the combining logic and relay drivers.

Regards,
Ray L.

1402

General Mach Discussion / Re: Speed controller won't hold steady speed - where is the problem?

« on: January 12, 2009, 10:58:03 AM »

I'm not using a C6, but a C11, and I have the same problem.  Often, first thing in the morning, the speed control is completely whacked, and commanding a very slow speed will result in a very high speed, or a wildly fluctuating speed.  After being powered for 10-15 minutes, it finally settles down and starts behaving.  It seems completely unpredictable, as some days it works fine, other days it doesn't.  I had one day that I couldn't get it to behave at all.  I gave up, and went back into the house for the day.  Came out the next morning, and it was working fine.  In every case where I've looked, the supply voltage from the VFD was fine, and the pulsetrain from the SmoothStepper was fine, but the output from the C11 was just whacked.

Regards,
Ray L.

1403

General Mach Discussion / Re: Limit switch location on axis?

« on: January 12, 2009, 10:53:49 AM »

Andy,

Ideally, the limit switches should directly cut power to the drives, WITHOUT depending on Mach3 to do anything at all.  This means having the switches directly controlling a relay.  The limit switches should be placed far enough from the physical limit of travel that once the limits are triggered, even if the axis is moving at it's maximum speed, the axis will coast to a stop JUST before hitting the physical end of travel.

Regards,
Ray L.

1404

General Mach Discussion / Re: nesting sub programs

« on: January 11, 2009, 11:36:08 AM »

On a semi-related note - What are the legal ways of entering comments in G-code?

Regards,
Ray L.

1405

General Mach Discussion / Re: Software to convert Dxf to Gcode, aka CAM. Recommendations wanted

« on: January 10, 2009, 11:01:31 AM »

Take a look at SheetCAM at www.sheetcam.com.  There's a free evaluation (I think 30 days).  You can also download their new tool SheetCAMTNG for free for, I think 15 days.  TNG is very nice at this point.  Support on SheetCAM is really first-rate.  If you do find a bug, it'll usually be fixed within days.

Cut2D is nice as well, and has a nice 3D simulation capability, but some of its other capabilities are rather limited.  I can't recall off-hand what it was I found lacking, but I did compare it to SheetCAM, and it came out second.

Regards,
Ray L.

1406

General Mach Discussion / Re: The Need For Speed. . . . At least for rapids

« on: January 07, 2009, 12:38:43 AM »

The maximum speed you can enter into the motor tuning dialog is limited by your kernel speed, which is the fastest rate at which the CPU can output step pulses.  If the driver test says you must run 25kHz kernel speed, then what you've got it what you've got, and you can speed it up only by either getting a faster PC, or buying a SmoothStepper.  On most PCs, 45kHz seems to be the practical limit on kernel speed, so at best you are likely to do no more than almost double your speed, without a SmoothStepper.

Regards,
ray L.

1407

General Mach Discussion / Re: How Many Tools Does Mach Allow?

« on: January 06, 2009, 08:23:00 PM »

Well, I solved my problem.  I just modified the post so it ignores the tool number passed in, and simply increments the tool number it passes to mach on each tool change.  So, as long as I never have a file that does 254 tool changes....  :-)

Thanks, Hood!

Regards,
Ray L.

1408

General Mach Discussion / Re: How Many Tools Does Mach Allow?

« on: January 06, 2009, 06:17:43 PM »

Hood,

   Thanks!  That's what I thought.  I already have an extensively customized SheetCAM post that does an explicit park before tool changes, and inserts an M00 prompting the user to put in the correct tool.  It also prompts me as needed to change motor speeds, pulleys, and any other conditions that require manual intervention.

Regards,
Ray L.

1409

General Mach Discussion / Re: How Many Tools Does Mach Allow?

« on: January 06, 2009, 06:02:27 PM »

I'm guessing the answer is 255, but I'd like confirmation.

Next dumb question:  I'm doing strictly manual tool changes, and not using offsets, length compensation, or any other tool parameters.  Given that, is there any reason I couldn't simply treat ALL tools as tool #1?  I can't see where Mach would care....

Regards,
Ray L.

1410

General Mach Discussion / How Many Tools Does Mach Allow?

« on: January 06, 2009, 05:57:35 PM »

I use SheetCAM to generate my G-code, and I've written some software to create SheetCAM tool sets from an Excel spreadsheet, with things like RPM and feed rate calculated based on SFPM and other factors.  I've created a huge toolset (about 250 tools), with numbers ranging from 1 to about 850 (yes, there's a good reason for that....), and Mach is really not happy with such large tool numbers.  Anyone know what the limit is?

Regards,
Ray L.