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Author Topic: Success! Mini Machining Center under Mach3 control - Video link  (Read 331560 times)

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Offline Hood

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #130 on: April 09, 2010, 05:24:37 PM »
Most industrial rated drives have differential Step/Dir inputs, they can usually be used single ended but I prefer to make my machines as noise immune as possible so I chose to use the differential capability.
The SmoothStepper doesn't have differential Step/Dir outputs, future hardware may be different though ;)
Wouldnt think many people use differential Step/Dir as I dont think any of the non industrial servo drives support it.

Hood
Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #131 on: April 09, 2010, 10:49:15 PM »
Is correct, output diferential in step/dir signal is more resistant to the noise that step/dir a ground.

I did the test putting the signal step/dir single ended hit to the motor and it lost many pulses, 
but the differential sign didn't lose none pulse.

regards

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #132 on: April 10, 2010, 05:36:45 AM »
OK, since the smoothstepper does not support differential signals, you must be doing the conversion downstream. My swapaxis board simply switches the signals unchanged, taking inputs from two axis and swapping them to the servo drives. The switching is very fast and should be transparent to the system, particularly to the smoothstepper driver.

Mach3 is unaware of the swapaxis board and even 'hot switching' with the axis moving seems to work OK. I have tested the board with the spindle axis active and running the spindle. Switching the axis in this situation simply starts the 4th axis running as the spindle. Switching back does not seem to confuse the system at all. The 4th axis is simply, silently, the A axis again, with the caveat that the position is no longer valid, so indexing requires a re-home. Also a 'hot swap' does not utilize accelleration settings to the axis sort of 'slams into gear' without a clutch . . .  so to speak, if you hot swap.

It seems to me that your setup *should* work like this: CNC->SMOOTHSTEPPER DRIVER->BOB->SMOOTHSTEPPER->SWAPAXIS BOARD->DIFFERENTIAL CONVERTER->SERVO DRIVE

Now that you have made me aware of differential step and direction signals being used on industrial drives, I have yet more homework to do. My new 'Super Duty' 4th axis is almost complete and it is not a hobby level machine, so I will need to support differential signals in the accompanying swapaxis board, so I will look into what is needed to accomplish that. Hopefully it will be something simple like dual multiplexers triggered simultaneously.

Offline Hood

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #133 on: April 10, 2010, 06:34:37 AM »
Simpson, if you look at the pic I posted you will see that the board I made connects directly into my PMDX 122 BOB with solid copper legs so no way I can take single ended signals off without removing that board :(

Hood

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #134 on: April 12, 2010, 09:47:30 AM »
I saw the picture. Very professionally done and neat as always, but not welded together from what I could see . . .   ;)

Hood, it was my impression that you have several or many machines all with smoothstepper and that you were interested in swapaxis capability except that the smoothstepper did not support it. I think it was you who said that anyway. Apparently one or more of those impressions in incorrect. Incidentally, I believe the swapaxis board could also go between the smoothstepper and the bob.

Eventually I will test is myself, but I am too busy right to inject the reportedly troublessome smoothstepper into the mix. The board works great between the BOB and drives using Machs port driver, And I have sent some out for testing on specific systems that will be getting the new 4th axis. The swapaxis function is critical to the usefullness of my 4th axis so all three of the little boards (TTl splitter/booster, relay and swapaxis) are being supplied with the machines. Several guys are building their own 4th axis based on this design and I may make these board generally available for people who tackle this themselves. None of these guys has a smoothstepper, but I just would like to know if it is compatible for future reference.  It *should* be, but it would be nice to hear it from someone who tested it.

So, anyone with a smoothstepper or equivalent (if there is one) and preferably also a 4th axis, send me a PM if you want to play and I'll send you a free swapaxis board to test and keep.

The machines themselves are coming along nicely. The lock is now also a brake and is completely enclosed in the frame. This is the Standard model. I'll be posting a new video soon of the Super Duty guy with the double reduction belts. That guy is a brute. I can't keep the main drive pulley locked onto the spindle . . so that model is 'still in the oven' so to speak until I get that issue resolved.



Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #135 on: April 12, 2010, 10:38:54 AM »
Wow, very professional looking unit.  That's the bearing right there in all its glory, eh?

I'd be tempted to put some sort of ring shaped cover over it, even though it is sealed.

Cheers,

BW

PS   I think US Digital has relatively inexpensive and compact converters to go from single ended to differential and back.  Like everything else, it's just a chip.
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Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #136 on: April 12, 2010, 12:01:03 PM »
Wow, very professional looking unit.  That's the bearing right there in all its glory, eh?

I'd be tempted to put some sort of ring shaped cover over it, even though it is sealed.
That's a good suggestion, thanks!

Quote
PS   I think US Digital has relatively inexpensive and compact converters to go from single ended to differential and back.  Like everything else, it's just a chip.

Yes they do, and Rutex also sells them and CNCdrives gives them away free with their drives. The converter boards are very simple (right up my alley  :-[), but I would prefer to support the differential signal directly on the swapaxis board, if it is not too complicated . . .  I can forsee just switching the extra signals or perhaps adding the differential converter chip to have a 'combo' depending upon what people want, but I just don't have time to address that at the moment. You are right about 'just a chip'  :D My little TTL splitter and also the Swapaxis are just chips also. The boards are basically just a 'connector' for the chips. The solid state relay is a little more complicated, but still pretty basic stuff. Anything electronic is a challenge for me and I have help in figuring these little guys out, but still it is fun and satisfying when they actually work!  The PCB routing is still fun and has now lead me into engraving  . . which is also big fun! CNC is a very addictive hobby, I must say.
My current 'rouge's gallery':




Offline Dan13

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #137 on: April 12, 2010, 12:06:36 PM »
Good looking boards, Steve and the 4th axis is just professional!

How did you do the printings on the boards?

Daniel

Offline simpson36

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #138 on: April 12, 2010, 12:24:19 PM »
Dan, I tried a number of methods including special ink in an injet printer and using a modified DVD printing tray, but in the end I settled (for now) on common rubber stamps using a 'permanent' ink. I would rate the results as 'satisfactory'. Silk screen would provide a better result, but I don't really want to mess with silk screening. I am however contemplating purchasing a pad printer for another project. If I go forward with that, then it would also do an outstanding job on the PCBs!

Hood, It has occurred to me that your smoothstepper is ahead of your BOB, which makes sense considering the smoothstepper uses a driver to 'talk' to Mach3. The swapaxis should still work between the drive and the BOB -or-  between the BOB and the smoothstepper, but in opposite order of the flow that I originally assumed.
« Last Edit: April 12, 2010, 12:33:34 PM by simpson36 »

Offline Dan13

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Re: Success! Mini Machining Center under Mach3 control - Video link
« Reply #139 on: April 12, 2010, 02:04:14 PM »
Ah... Interesting! The results sure look good. Do you engrave the words in the rubber first, or how is it done...?

Daniel