Joint 0 Following Error

[coffeetek]

So on the heals of the problems with my 440 now I have problem with lathe as well. Today while running a program which I have been running for months machine started erroring out. This program is simple facing program, it faces part and then pulls back for second pass. On pull back machine e-stops with joint 0 following error message.

Please see this video which shows the program and machine working and then erroring out:




Notice following line of code: G96 D2500 S80 M3


If I change that to: G96 D2000 S80 M3


Machine will not error out. So maximum speed reduced to 2000 RPM will not error out, but if it goes to 2500 it will generate error. To repeat I have ran this program for months exactly like this without any problems.

Anyone have any suggestions on what this could be?

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[MichaelHenry]

A WAG - could the spindle be momentarily exceeding 2500 rpm, as indicated by the encoder? Maybe that's throwing an error.

[coffeetek]

A WAG - could the spindle be momentarily exceeding 2500 rpm, as indicated by the encoder? Maybe that's throwing an error.

I think so too, I think its a bug in Path Pilot 2.0. Combination of constant surface speed and X going slightly into the negative throws off the system.... Will test it out when I have some time.

[dgibbs]

Yes I ran into this as well, definitely spindle speed issue try using G00 on the retract instead of G01.

Also check if you have C5 collet selected under Settings if you have the Chuck selected that will do it too.

[dgibbs]

RDSI

Interesting I will check my machine when I get back to it.
Support acted like never seen this before...

[Aracheon]

You might want to consider the issues I pointed out in this post: CSS Mode Not Working Correctly.

Basically I found that the VFD is not programmed from the factory to use the braking resistor, even though there is one installed. When I called Tormach on this they agreed with my finding but have never since followed up.

Without the braking resistor enabled the spindle can and does coast more than it should especially when using the 3-Jaw chuck. Until I modified the VFD programming to use the braking resistor I found many situations where spindle speed was going faster than it’s programmed speed when beginning a cut as pointed out in my post above.

Maybe PP2 has become more sensitive to this issue and now throws an error when it sees that the speed is higher than it should be?

How did you program the VFD to use that resistor? I just hit this same problem on my Slant this week after swapping to the 3500rpm pulley for some smaller 5C work.


EDIT: Nevermind... just clicked your link to the other post. I can haz read good.