Position Verification The "Ruppe" Test: DMM DYN4 Encoder signals piped into Acorn's Spindle Encoder

[martyscncgarage]

Terry Ruppe of Arrow Controls came up with the idea.
I decided to give it a go on my Emcoturn 120 lathe fitted with DMM DYN4 AC drives.
Seems an accurate way to test for lost/gained steps as the encoder is providing feedback to Acorn to display.
You do have to make up a cable that matches the DYN4 encoder pins(or any other drive that provides standard encoder signals) to the Acorn Spindle encoder pins.

[ScotY]

That’s very interesting, Marty. I haven’t been hanging out here much lately so wondering if there was a reason for the test? Being a quality servo, wouldn’t you expect no error? I think it would be equally interesting to run the same test at a lower feedrate. On those rapid moves, you can see the encoder signal lags behind, as one would expect.

Question...if you ran a program at a very high feedrate and one axis had to move significantly farther than the others, would an error be introduced in the part? Hope that makes sense?