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Author Topic: Multiple MPG - Can this be done ?  (Read 2751 times)

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Multiple MPG - Can this be done ?
« on: May 14, 2014, 05:23:57 PM »
All,

I have the desire to attach a handwheel with encoders to the "X" , "Y" and "Z" axis of my mill in an attempt to create a "manual type" machine.
I know thats not a hard thing to do physically , but is there a way to do it and enable all axis to allow MPG input without having to select the axis in Mach first ?

It would be a real pain to have to select the an axis to move in Mach then turn an axis handle, stop , then select another axis in Mach then turn the handle etc . etc.

Hope this is explained well enough, any ideas sure would help

Thanks

Offline RICH

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Re: Multiple MPG - Can this be done ?
« Reply #1 on: May 14, 2014, 06:47:18 PM »
Use two MPG's here for the lathe and mill. Just go in and define the pinout in Ports & Pins and you will see three MPG's are available.
To mimic manual hand wheel function just play with the counts per unit and velocity for the feel / movement you desire.
 
Inthe Jog flyout you can assign what mode you want.

No pain at all to use.......
RICH

Offline Hood

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Re: Multiple MPG - Can this be done ?
« Reply #2 on: May 14, 2014, 06:48:32 PM »
I have never personally used multiple MPGs but I have seen some mention they have, think maybe Rich and John Prentice.
I think if you set up multiple MPGs then you should be able to use all at the same time (if you have 3 hands ;D )
How they are designated I am not sure but I must presume, as there doesnt seem to be any other way, that MPG1 will be for X, MPG2 will be Y and MPG 3 for Z.

Hopefully someone will be able to give you a definitive answer.

Hood

Ahh see Rich beat me to it :)
Re: Multiple MPG - Can this be done ?
« Reply #3 on: May 14, 2014, 07:06:47 PM »
Ya know after I posted the original message I did have a realization that I did at one time remember that there were multiple MPG's configurable
under ports and pins. I do believe that thats exactly how multiple MPG's might be addressed.

Its really cool to have a CNC but ALOT of times I just need to square up blocks and do manual mill type type work.

Im going to attempt to build encoder driven handwheels ..... Ill keep everyone informed .

BTW I only have 2 hands ..... but a well trained "third member" if ya know what I mean .......hahaha

Offline RICH

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Re: Multiple MPG - Can this be done ?
« Reply #4 on: May 14, 2014, 07:18:56 PM »
The profile in use defines what MPG will be used for what axis. Click Tab and then in the flyout you can define what MPG belongs to what axis.
Since i only have two and the pinpout is the same but the counts and velocity are different for my mill and lathe.

RICH
Re: Multiple MPG - Can this be done ?
« Reply #5 on: May 14, 2014, 07:25:53 PM »
So you've accomlished this already which is great news......does it work well and did you have to make detents to keep the handwheel from moving accidentally?
What encoder count did you end up using?

Offline RICH

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Re: Multiple MPG - Can this be done ?
« Reply #6 on: May 14, 2014, 07:27:57 PM »
Watch out if your using them to actualy machine something.
Sneeze while turning the mpg can mean one heck of a gouge into the material, broken tool......
Don't ask how i would know that.  ;D

BTW, for machining an xbox controller can be used with some practice as a lot of settings and control  are available.
My friends use it all the time but I don't since i don't feel confortable using it for machining.

RICH

To each their owne...........
Re: Multiple MPG - Can this be done ?
« Reply #7 on: May 14, 2014, 07:34:21 PM »
I did build an MPG by using a 100 c.p.r. encoder and it works great , nice and smooth but it did take alot of time to make sense out of the Mach settings.
The MPG I built does have detents, but like you mentioned......just one "bump" of your hand or something else and there goes the farm...

Offline RICH

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Re: Multiple MPG - Can this be done ?
« Reply #8 on: May 14, 2014, 07:38:06 PM »
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does it work well

yes and don't know if i could live without them

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did you have to make detents to keep the handwheel from moving

Friction keeps the wheel from turning on mine, detents may be fine if you want to have a feel / indication for amount of movement.
I mostly use mine to touch off tools, and for the lathe, a full turn is around 0.012" but without looking at the screen very easy to move in small increments
like .0002" since i can hear the steppers step.

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encoder count
would need to look it up as i don't recall it's been that long :D

RICH
Re: Multiple MPG - Can this be done ?
« Reply #9 on: May 14, 2014, 07:44:49 PM »
After thinking about it . the encoder count woudn't really mean anything because of ball screw pitch and pulley reductions etc. etc.
One thing I did discover is there is a direct correlation between the encoder counts and the achievable jog speed.

Its quite amazing the things you learn by tinkering with kind of stuff.