Trouble getting dual MPGs to work on lathe - New Oak install

[RTech]

I've been trying to figure out how to get the X and Z hand wheels (MPGs) working on my new Oak lathe install.

So far, I have installed and wired two 100 pulse MPGs with one using the encoder input on axis 3 and one on axis 4. I have also set MPG parameters #348 through #353 correctly as well as #218 and #400 to 0.

When I go into the PID menu, I can see both MPGs and have verified there are 400 counts for one revolution on both.

I've been in contact with a forum member here and helpfully he sent me a report of his setup. I did find a few differences in the MPGStage when I compared both in Notepad++, so I tried a cut & paste, but still no go. I'd rather not try his full .scr file as it has a few other modifications and I'm still trying to learn how to read and edit plc files...rather focus on one thing at a time.

I did have a go at comparing the parameter settings, but I didn't see anything that stood out.

A report is attached.

I'll do more reading this evening, but any help is appreciated.

Jim

[tblough]

Have you pressed the MPG button on the control panel and is the MPG button light lit? I checked your parameter settings and those are correct. If the encoder is counting on the PID screen, then they should be working.

[RTech]

Tom,

I did an edit of your .src file this morning to remove items that are not in my lathe's setup, added some stuff for the collet closer, complied it and the hand wheels work! I'm not sure what made the difference...I still have a lot to learn about reading the code. I'll have to compare the files in Notepad++ and try to figure it out.

For now, all things seem to function well.

Thanks again,
Jim

[tblough]

Jim,

Glad you got it working! I didn't run the numbers on your ballscrews, but you might want to increase your handwheel encoder counts. IIRC, you had them set to 400. That makes for a fairly large move per encoder count especially on the X since one encoder count is actually two off the diameter.

More encoder counts also means it's less susceptible to vibration. Vibration on the handwheels is transmitted to the encoders and can cause jitter on the encoder output which, with a low encoder count, could show up as actual slide movement back and forth.

[RTech]

Thanks for the info. I think I may go with optical encoders in the near future.

The hand wheels are standard 100 detent units. The detent clicks make manual use movements a little "notchy".

I think optical encoders with some sort of adjustable resistance or "drag" would probably work best.