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Messages - TunerTom

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General Mach Discussion / Re: Really need help

« on: August 14, 2009, 02:22:12 PM »

Jeff,

I'm the first person to admit, I am ignorant.

I'm an organbuilder, not a machinist, and I have no experience with CNC. I do have some programming skills and I have an X/Y plotter. The plotter was built by the guy who did the lathe. I have an older laptop that uses Windows-98SE and it has a parallel port. I can run the original BASIC programs in a DOS wiindow, and the plotter will trace the actual toolpaths on paper. The plotter is fitted with a digital counter that counts up or down. revealing the X/Y position in terms of the number of pulses sent.

I inserted break points at the end of each line or arc and ran the BASIC profiles. From that I wrote all the values displayed on the X & Y counters and put them into an Excel spread sheet. I was able to extract radiuses for the curves from the BASIC source. I then worked these spreadsheets to generate simple G-Gode scripts, which I saved as text files.

I also have my main PC... just loaded with software running XP. It too, still has a parallel port.

I added a second parallel input to the plotter and wired the output end to the appropriate points in the builder's interface with Mach3 requirements. The Point is, I can plug my laptop into the plotter and run plots of the profiles on paper... unplug the laptop and run my g-code profiles using the alternate socket on the plotter from my main PC through Mach-3, and trace right directly over the original BASIC plots, using my Win-XXP Desktop. It took some tweaking of the g-cod, but it works!

Based on this, I was convinced that I could convert the lathe to use Mach-3. I still believe this is possible, but I'm totally at a loss as to what to try next. I have to try something. I'm paying out of pocket for my hardware mistakes. It isn't fair to ask my employer to do this...

So yes, I am ignorant.

We turn drawknobs for our consoles (see attachment)...

General Mach Discussion / Re: Really need help

« on: August 14, 2009, 01:21:45 PM »

OK Simpson36, let's try this...

I will order the C1 - Parallel Port Interface Card as soon as I hear from you about the following relay board
I have a relay board that I bought with the RF Isolator. It has screw-terminal inputs & outputs. Any reason you think I should replace it with your C15 - Dual Relay Board?

The DOS machine and its interface is disconnected for now. I don't plan to reconnect that unless I can't get the Mach-3 system working.

Thanks for your advice...

General Mach Discussion / Re: Really need help

« on: August 14, 2009, 08:04:38 AM »

I'm truly sorry if I have offended anybody. It was not my intention.

I think the best thing for me to do now, is to wait until the scope I ordered arrives.
Is it fair to assume the place to scope the pulse train is across the outputs on my Probotix RF Isolator? That is what is going into the drives...

I think I also need to tell you all, that this lathe was built and outfitted by a private individual. It was operated by a DOS computer, and the interface electronics between the parallel port and the Slo-Syn drive was also scratch-built. The profiles were written using Microsoft BASIC and are (for me) a nightmare to edit. We are hoping to move forward here, to use industry-standard software. This interface is disconnected for the time being, but I can, and have, reconnected it and the lathe still works properly from the old DOS machine.

Because this can still be made to work, I feel reasonaby confident that there is nothing wrong with the drive, the stepper motors or the wiring (at least from the output of the drive)...

General Mach Discussion / Re: Really need help

« on: August 13, 2009, 05:01:34 PM »

Thanks Jeff,

This skipping steps issue is the only thing keeping us from doing production.
I will tell my employer and suggest he consider springing for a smooth stepper.

I have an inexpensive digital scope on order. I hope to use it to see if I can see irregulatities in my pulse stream...
I'm also tempted to buy a digtal up/down counter kit and see if I can count the pulses and compare with the number of steps required to move a given distance.

General Mach Discussion / Re: Really need help

« on: August 13, 2009, 04:31:38 PM »

Hey Guys... I hate to say this, but I fear we are straying from my original question.

I think we might be digressing from the original subject a bit...
I went to the shop today and I stripped Windows XP of all of its extranious bits, as outlined in a Mach-3 document I have.

I tried running my profile, and for abiout three runs, the X-Hand-wheel returned to its starting point and the Z-Handwheel fell four steps short. I thouht things were getting better. Actually, for what I am turning, I could live with jogging "Z" back to zero a few steps and correcting the Z-DRO., but on the fourth try, "Z" fell short by 25 steps... Not acceptable! I tried slowing the motor's max speed settings down from 250 to 200. I don't like the way G0 sounds at 200 mm/Min and the end position never got better.

So, perhaps trimming Windows down is necessary and a good thing, but it hasn't helped getting my tool post to return to its original position.

Then I tried my experimental g-code to run "Z" back & forth several times, then run X back and forth several times. The program moves "Z" from 0 to 128, then back to zero three times at full speed using G0. Then it runs "X" fore & aft from 0 to 128 and back to zero, three times . I tried setting motor speeds at 200, 250, 300, & 350. With each increase in speed the motors sound smoother and get faster and every end run. Every time the script finishes both hand-wheels end back up at zero... every time! Then, I noticed something strange...

As the saddle moves from zero to 128 in either axis, I hear a "glitch" in the motorthat's operating... like it just skipped a step or two. Then on the return from 128 at about two-thirds of the way back (same as 1/3, the way out) , I hear the glitch again. This occurs on both the X-Axis and the "Z"-Axis... wierd! I put a mark beside the rails on each axis. It's like clockwork., When the saddle reaches either mark, from either direction, there is this little "bzzt". The faster the motors are running, the harder the "glitch" is to hear, but nonetheless, it is there.

I wonder if both these motors are skipping pulses every time and the lost pulses in one direction compensate for the same number of lost pulses in the opposite direction. That way, in this situation with one motor running at a time can always return the hand-wheel to zero??

Tell me I'm nuts!

Anybody know of a simple kit to build a TTL pulse-counter with about six digits of display?

General Mach Discussion / Re: Really need help

« on: August 13, 2009, 04:36:50 AM »

Simpson 36...

Thanks for your information. This is all sort of new to me. I will look more closely at the applied voltage to the motors.
The Parallel port monitor is not TSR. It is not running when Mack3 is. I used it to set/clear data bits to see what effect they had.
I will find your post. and look into all matters you have outlined above.

General Mach Discussion / Re: Really need help

« on: August 12, 2009, 08:16:55 PM »

The motors are 3.5 volt so I assume the drive is outputting something close to 3.5VDC? I didn't build that part of the lathe. I do have a scope coming... so I can measure the voltage then.

I can say, the motors have PLENTY of torque... I don't think I can stall them by holding the hand-wheels on hte lead screws.

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