Messages

591

General Mach Discussion / Re: Unit of measurement for accelleration

« on: November 21, 2010, 02:22:55 PM »

Thanks very much Hood.  Makes sense now.

592

General Mach Discussion / Re: Unit of measurement for accelleration

« on: November 21, 2010, 01:16:19 PM »

Can't seem to get my head wrapped around it.  How would to write it out as a mathematical formula if the accell were 50 and the velocity were 500?  What I'm trying to do is come up with the time it takes to accelerate from 0 to 500IPM with an acceleration setting of 50.

Thanks

593

General Mach Discussion / Unit of measurement for accelleration

« on: November 21, 2010, 11:51:20 AM »

On motor tuning when you set acceleration of say 50, what unit of measurement is that?  I think it's ??/sec, but I can't remember.

Thanks

594

General Mach Discussion / Re: MACH NOT ROUTING RIGHT

« on: November 19, 2010, 10:16:31 AM »

I would bet the problem is the Stepperworld drive.  Those are OK for experimenting but not much good for driving a real machine.  They may have a better product now, but I tried their stuff about 8 years ago and couldn't get anywhere with it.  If I recall, the drives were not constant current and required power resistors.  It could also be something binding on the Y axis, but based on your V and A numbers, I'd bet on the drive system as I recall about the same results with an Ebay/StepperWorld drive.

We use the G540 and NEMA23 425oz/in motors on a 4x8 gantry plasma/router.  It will rapid at 800IPM with an accel of 100 without losing steps.  We've also used the Keling 381 when we run short on 425's with the same results.

595

General Mach Discussion / Re: MACH NOT ROUTING RIGHT

« on: November 18, 2010, 09:18:51 AM »

Sounds like the velocity, accel or both are set too high.  The Binding noise sounds like motor stall.   I can set my velocity and accel very high (1200 and 100), and it will jog fine at those settings, but a rapid G00 move in either X or Y will stall the motors.  If I lower the velocity to 800, it runs all day long with no problems.

What is the belt reduction on the pinion?   What is your velocity and accel set at? 

 

596

General Mach Discussion / Re: gcode G00 Y -40

« on: November 15, 2010, 09:25:48 AM »

If the G00 Y-40 is the first move in the G-code, then it sounds like your part is set up in ArtCam 40 units on the Y axis from zero origin.  If that's the case, when you zero the DRO's in Mach and run the part, then the first move would be a rapid move to where the part is oriented in ArtCam.

597

General Mach Discussion / Re: E Stop

« on: November 11, 2010, 09:33:01 AM »

You could also do it without a relay using a DPDT estop button. Use one side to disable the drives and use the other side, wired NC, as an input to Mach.  Set the input as active high and when the button is pushed and the switch opens, mach triggers an estop, while at the same time your drives shut down.  I agree with Hood in that high voltage relays are better in a noisy environment.  Never had noise issues though, even running HF plasma.

I started using the G540 drives and this functionality is built into the drive.  When I disable the drive with an external estop, it sends an estop request to mach.  I think that is built into their internal BOB.

598

General Mach Discussion / Re: Plasma Table

« on: November 08, 2010, 09:57:26 AM »

I don't see the need or benefit in making the gantry articulating.  There would be no need to skew the gantry during a part run.  The only advantage I see is that is the gantry goes out of square, it wouldn't bind, but if it's going out of square that often and binding, there is a problem that needs to be addressed.  Barring a visit from Murphy, the gantry should stay square.   

599

General Mach Discussion / Re: Homing slaved axis with a common switch

« on: November 07, 2010, 11:07:11 AM »

Cool.   I figured I'd need change the referencing code to something like this...

DoButton( 24 )
DoButton( 23)
RefCombination( 9 )

600

General Mach Discussion / Re: Homing slaved axis with a common switch

« on: November 07, 2010, 08:57:00 AM »

So could I just keep what I have, which is XYZ home and limits on one switch and just add an A home/limit on the other side of the gantry on it's own input?  That would separate the A switch from the rest of them.  That should work, right?  problem is that I only have one unused input, so I can't separate all of the home inputs.

Thanks