MaxNC T2 lathe
It has 3 or 4 PIC 16F84A chips as the brains.
The Steppers have encoders on the back and the encoders plug into the drive next to the motor plug.
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I have to say, that doesn't sound all that promising.It has 3 or 4 PIC 16F84A chips as the brains.
The Steppers have encoders on the back and the encoders plug into the drive next to the motor plug.
Do you have the original software ?
You could, possibly, watch what comes out of the parallel port when running that. You would need to use an oscilloscope, but Halscope (built in to EMC2) is perfect for scoping parallel port pins. I think with the EMC2 PC parallel port set to "input" mode you will even be able to scope them all at the same time.
Halscope is described here. You can start it from the halrun prompt as described in the link, or from the Machine menu in EMC2/Axis:
linuxcnc.org/docs/html/hal_tutorial.html...orial%20-%20Halscope
Parport in Input mode:
www.linuxcnc.org/docview/html/hal_drivers.html
EMC2 can definitely drive your lathe, but I can only be confident about that because EMC2 allows you to write your own hardware drivers. There is a definite question about how hard it will be.
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I haven't touched the ini at all, and the hal is a little hacked in my attempts to apply some examples and google searches to it.
The 3 longer chips are the PIC 16F84A's and the 4 near the top are SN7400N
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. The hal looks OK, though I think your Google searches must have turned up some very out of date docs.the hal is a little hacked in my attempts to apply some examples and google searches to it.
The sequence:
newsig xA bit
linkps stepgen.0.phase-A xA
newsig xB bit
linkps stepgen.0.phase-B xB
linksp xA parport.0.pin-08-out
linksp xB parport.0.pin-09-out
net xA <= stepgen.0.phase-A
net xB <= stepgen.0.phase-B
could be shrunk to:
net xA stepgen.0.phase-A => parport.0.pin-08-out
net xB stepgen.0.phase-B => parport.0.pin-09-out
As "net" automatically creates a signal of the right sort and links it to all the other items on the same line.
Are you sure that pin 17 needs to be held low?
The 3 longer chips are the PIC 16F84A's and the 4 near the top are SN7400N
I guess the nands are just buffers, but could be wrong.
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I don't hav the original software, but do have an older o-scope I'll haul out and see what I can see coming out of the pics.
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It is just possible that you might be able to pull out the PICs and take one of the 4-wire config stepgen outputs direct to the power stage.
(possibly a lot of work though).
It is entirely possible that the closed-loop MaxNC machines communicate position information with a serial protocol. Have you tried contacting them to see if they are willing to help?
Looking at the web site, it seems that a preconfigured laptop to drive the machines adds $300 to the price of a system. Depending on your priorities that might not be the worst option.
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The high pitch whine comes from hooking xenable to pin 17. If I turn pin 17 on manually or on inverted manually the motors make a little jerk then remain unresponsive to controls.
If the whine in happening I can feel small attempts at movement when I manually move the axis.
I should add I have removed the leadscrew from the motor so it doesn't have any load to worry about just now.
correct me if I'm wrong but HALScope will show me what is being output to the pin itself. Would it be useful for me to pull out my o-scope and look at whats going into the motor and or encoder wires themselves?
My scope has 2 inputs, and runs at 20 MHZ old green tube thing.
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Googling that gives this word document I'm now poking through for clues
ftp://machsupport.com/XMLs/Mach%203%20an...10%20Open%20Loop.doc
If you don't have Word google docs seems to open it fine.
This shows that pin 10 has to be "enabled" which I thought mean to peg the output high. However looking at hal_drivers documentation I see that it is an input pin.
Would hooking this up to a signal do what is required?
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ftp://machsupport.com/XMLs/Mach%203%20an...10%20Open%20Loop.doc
That all looks quite promising.
This shows that pin 10 has to be "enabled" which I thought mean to peg the output high. However looking at hal_drivers documentation I see that it is an input pin. Would hooking this up to a signal do what is required?
No. it might be required for Mach to work (possibly) but the motor driver won't know. It might be interesting to watch that pin though.
In fact, have you tried manually toggling pins with the Parallel Port Tester?
wiki.linuxcnc.org/emcinfo.pl?Parallel_Port_Tester
it might be instructive.
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