Messages

1

Brains Development / Re: Drive stepper motor via Brain for ATC

« on: April 01, 2009, 04:34:15 PM »

I'm guessing since no response that this isn't possible and I need to do the ATC with a macro?

2

Brains Development / Drive stepper motor via Brain for ATC

« on: March 27, 2009, 11:24:52 PM »

I'm trying to write a brain to run my rotary tool turret on my lathe.  A little background on the tool change operation first:

When a tool change is called:
1) turret raise solenoid fires to raise the turret off its stop dogs
2) proximity switch sees turret has been raised and allows mach to rotate turret
3) stepper motor rotates turret proper number of degrees
4) stop solenoid fires a stop pawl to give positive stop to turret rotation
5) turret raise solenoid shuts off to drop turret back on stop dogs
6) proximity switch sees turret has dropped and allows mach to continue program

My immediate question is: how do I terminate a lobe to command rotation of a stepper motor a certain number of steps while running g-code which has called for the new tool (i.e. not move via jog)?

Thanks,
-Ryan

3

General Mach Discussion / Re: Stop Mach from ignoring limits when homing

« on: March 24, 2009, 08:21:08 AM »

Thanks for the input guys.  I agree, it's always best to make sure you're on the proper side of the home switch before homing, but on this machine, the x-travel is only ~4.5" and the home switch is closer to the center of travel than the end; i.e. not always obvious if you're slightly to the wrong side of home.

I like you're idea greolt, unfortunately, Hardinge had a way of cramming an obscene amount of mechanics/electronics in very small spaces.  Not to mention the fact that the mechanism that trips the home switch (and limit switches) on the x-axis is very elaborate and I'd rather not modify it to hold the home switch on if you're on the wrong side.  On an easier machine, definitely the way to go I would say though.

I wrote up a quick Brain to monitor the limit switches and trip a stop if it sees one.  I didn't figure Mach would be monitoring the limit inputs at all (the LEDs don't light on the diagnostic screen when you come on a limit and you're homing) but the brain does seem to trip the estop still.

Thanks again, hopefully this will work!
-Ryan

4

General Mach Discussion / Re: Stop Mach from ignoring limits when homing

« on: March 23, 2009, 10:07:23 PM »

My limit switches arent mechanical switches, it's a hardinge CHNC lathe so they used fancy hall effect switches.  Wiring the estop string through them would require some significant changes to the overall machine wiring. 

My other concern about Mach ignoring the limits is, what happens when you tell the machine to home and you're on the wrong side of the home switch...the axis will drive to the mechanical stop since Mach won't trip the limit.  On this lathe, it's easy to be on the wrong side of the home switch, trust me, I hit the limit switch many times when attempting to home when it had its original control on it.

Is there a way to overcome (through software) Mach's ignoring of the limits?

5

General Mach Discussion / Stop Mach from ignoring limits when homing

« on: March 23, 2009, 08:07:09 PM »

My lathe has separate home switches from limit switches on both axes so I don't need (or want) Mach to ignore the limit switches when doing its homing procedure.  I had a home switch fail today and the machine ran to the mechanical stop since Mach ignored the fact that the limit switch had actually been tripped.  Is there a way I can tell Mach not to ignore the limits when homing.  Or, alternatively, can I write a brain that does the homing for me in which the limits aren't ignored?

Thanks,
-Ryan

6

General Mach Discussion / Re: CHNC retrofit

« on: January 30, 2008, 10:54:15 AM »

Vince,

Sorry, I didn't notice your post before. 

I'll have to take some pics of the setup to show you what I did exactly but I'll tell you quick anyway.  I couldn't find a stepper to fit directly where the airmotor was so I mounted one on the steel plate at the end of the carriage (the plate the wires pass through) and ran a driveshaft out to the worm.  Actually, I used parts from the old airmotor to mount the driveshaft in the casting.  The only downside is that you need to put a 1/2" spacer between the rear cover and the carriage to clear the stepper...not a bad compromise I figured though.

I'll try to get some pictures for you when I get a chance.

I don't know much about the worm as far as part numbers go...I just used the one that was in the machine originally.

-Ryan

7

General Mach Discussion / Re: ATC using stepper motor on A axis

« on: January 30, 2008, 10:53:41 AM »

Vince,

Sorry, I didn't notice your post before. 

I'll have to take some pics of the setup to show you what I did exactly but I'll tell you quick anyway.  I couldn't find a stepper to fit directly where the airmotor was so I mounted one on the steel plate at the end of the carriage (the plate the wires pass through) and ran a driveshaft out to the worm.  Actually, I used parts from the old airmotor to mount the driveshaft in the casting.  The only downside is that you need to put a 1/2" spacer between the rear cover and the carriage to clear the stepper...not a bad compromise I figured though.

I'll try to get some pictures for you when I get a chance.

I don't know much about the worm as far as part numbers go...I just used the one that was in the machine originally.

-Ryan

8

General Mach Discussion / Isolated ground question

« on: January 21, 2008, 07:29:19 PM »

So my CHNC retrofit is well underway and I'm getting ready to button up the PC and drive components.  Unfortunately, I've run into a question that I can seem to answer...

I need to know if I should keep the ground(s) of my motherboard, breakout board, and Rutex drives isolated from the system chasis AC ground?  I originally thought it would be best to keep them isolated for noise purposes and had been putting it together as such, but then I found that the chasis of my Rutex motherboard connects to the shield of its LPT port which will connect to the LPT port on the motherboard which will tie the PC directly to system ground.

What does everybody else do??

Thanks,
-Ryan

9

General Mach Discussion / Re: E-stop & reset question

« on: December 17, 2007, 07:44:29 PM »

Tony, thanks for the reply.  So if I turn the "Charge pump on in Estop" off, and use the charge pump circuit to trigger the physical estop I should be all set then...  I didn't know about you could kill the charge pump in the event of a general estop.

Thanks!
-Ryan

10

General Mach Discussion / E-stop & reset question

« on: December 16, 2007, 07:13:35 PM »

I would like to know if it is possible for me to setup Mach so that when an estop from the PC is triggered, an output pin can trip a physical relay and trigger a physical estop.  I'm using Rutex drives which will trigger an estop on the PC when an axis limit is hit, but I would like to have a physical estop string which can be tripped when this internal PC estop is triggered.

In combination with this, I want to have a physical reset switch to take the place of the one on the Mach screen...I'm pretty sure this can be done but want to make sure.

-Ryan