My new project

[JHChoppers]

Thanks for the compliments Monty! 

I am watching your build to learn as much as I can about lathe conversions, as I plan to convert this SL1 to Mach3 someday…

JH

[Monty]

JH,

Nice looking lathe. I'd definitely get familiar with modbus and PLC's for that one. I'm starting to wish I had used a PLC and modbus with a galil card and AC servos. I keep having a flaky random problem with some kind of noise or cold solder joint somewhere. It's driving me crazy. Impossible to track down random problems. Just about the time I get ready to make some real parts or get comfortable with it WHAM!! flaky problem returns.

Anyway, during one of it's lucid moments it managed to demonstrate the tool changer, tool table, and flood coolant today:

http://www.youtube.com/watch?v=7AQGT7AnlD4&feature=player_embedded

Monty

[JHChoppers]

I feel your pain about flaky problems, the PC I had running my smaller BP CNC Mill went down.  Not big deal, just save off the data and replace the PC, right?  It took a month to get it working again, the parallel port had different impedance, so some of the inputs would trip randomly.  After a rewire with a new breakout board,  shielded cables and only grounding one side of the cables to a common ground, things are better than before!

Try breaking it down into small pieces and function test each one, then integrate them together slowly and methodically while testing each system along the way.

On my big VMC that I working on in my spare time, I am using Modbus to the control the spindle and monitor the spindle load.  Modbus is great!  
http://www.machsupport.com/forum/index.php/topic,13365.0.html

Keep posting...  

JH

[Monty]

Thanks JH,

Basically what happens is the thing is rock solid. Then it will randomly have either an e-stop or limit switch trip. Once this starts up It usually doesn't calm down until I turn the machine off for a while. This doesn't always work and sometimes it's still flaky when I start it back up dead cold. Once the problem starts, I push the reset and it immediately trips. The DRO for spindle RPM starts jumping around also. So basically all the inputs start going haywire. If I then disconnect the spindle speed sensor from the board the BOB really starts going haywire with LED's and relays clicking away like Morse Code.

I've been through the whole machine. I've basically got it isolated to the breakout board. I can disconnect all the external wiring from the BOB to my machine except the power, and replace the E-stop and Limit SW with a jumper but the problem is still there. Even with all the 3 phase stuff completely disconnected from the wall. So it's not noisy wiring or a ground loop.

If I disconnect the printer cable at the BOB the problem goes away. I have also made a new printer cable and still have the problem. I really think it is a problem in the BOB.

I ALWAYS shield things and ground at one end. Also use a single point ground. Put snubbers on all the AC coils and diodes on the DC ones. Also run all AC lines separate from DC. I also try to separate all signal lines from stepper motor lines, but I couldn't do that to the turret. They are both shielded and routed in a shielded conduit. I've learned all that the hard way.

I have wondered if the Parallel port might be bad or something, but the PC and Mach are rock solid with BOB disconnected. Problem also occurs when the machine is hot or cold. So cooling isn't the issue. The hardest thing is that it is random, so if you make a change and the problem disappears, I think HEY I GOT IT!!!. Only to have it start acting up when I'm loading stock for a project.

Ah well.....keeps me off the streets.

Monty

[Dan13]

You may have already tried it Monty, but since you didn't mention it - did you try setting a bigger debounce in Mach?

Daniel

[Monty]

Daniel,

Yep tried it. It doesn't help and I can't set it very high without mach missing some of the position strobes on the turret encoder.

I think I have found the problem. I have to do some more testing to make sure.

Monty

[Monty]

Solved the problem on the lathe. It was a combination of not one, but TWO bad printer cables. I thought I had eliminated that variable by making up a new cable.

There was also a cold solder joint on the BOB.

All is well now:

http://www.youtube.com/watch?v=9B2d5HABSJk

Trouble shooting can be a real pain sometimes.

Monty

[Dan13]

Well done Monty! Was not easy tracing it down. Glad you got it solved in the end.

Very good video also. What are you using for coolant?


Daniel

[budman68]

What a fantastic machine, Monty, thanks for sharing-

Dave

[Monty]

Daniel,

I'm using Astro-Cut Synthetic in distilled water.

Tracking down bugs can really be a bear sometimes. Even if you think you have eliminated a possible problem sometimes you just have to start over from square one and go down the list. That is the only way I found out I had two bad cables. So sometimes trying the same thing over and over and expecting a different result is not insanity . That's my story and I'm sticking to it.

Thanks,

Monty