[topgraver]

Hi, I wired the encoder to my lathe using the mk2 board and using the original USB CNC software. The encoder I used is Omorn E6B2-CWZ1X with 2000PPR. I set the same PPR in the setting and index as 1. Although this encoder has negative A, B, Z phase, I only wire the positive ABZ phase to the board and by checking the IO interface it showed up correctly. I noticed on the left corner of the software display screen, the real-time RPM seems to be "too sensitive", it keep jumping around even with slight movement of the encoder. This cause the threading not functional. I would like to ask what could go wrong here. Is the resolution of the encoder too high or there could be something else I didn't consider of. Thanks.

[Jim Dawson]

It could be too many lines for the counter on your board to keep track of. Is there an anti-jitter setting in your software?

I have a 1024 line encoder on my lathe spindle, threads just fine, but I do have a very high speed counter on my controller. Maybe try a 500 line encoder.

[topgraver]

Thanks for the reply. I got another question, my spindle to encoder is actually on 2:1 reduction ratio. Does the PPR setting in software be the encoder PPR/2?

[Jim Dawson]

Thanks for the reply. I got another question, my spindle to encoder is actually on 2:1 reduction ratio. Does the PPR setting in software be the encoder PPR/2?

If the encoder is turning 2x the spindle then you would set the PPR in the software by 2x also, or if the encoder is turning 1/2 the spindle, then you would set the corresponding value in the software.

But there is another problem, you mentioned that it would not thread properly. The Z pulse only fires once per encoder revolution, thus you are getting either two Z pulses / rev, or one Z pulse every two revs of the encoder. If your threading is triggered by Z pulse, then either way it is not going to work properly.

I looked up that encoder, in most cases with a quadrature output of 2000 PPR, this would give you 8000 counts / rev, assuming your controller counts on both the rising and falling edge of the square wave. You might want to look at the raw encoder count data to confirm what your controller is reading for one revolution of the encoder.

[mactec54]

Thanks for the reply. I got another question, my spindle to encoder is actually on 2:1 reduction ratio. Does the PPR setting in software be the encoder PPR/2?

So then in your settings the Encoder output would be 2:1=Half which would be 4000 if your encoder is Incremental

Check the Grounding of the encoder this could be the cause of the jumping around, this Ground wire would have to be connected to the Board you are using

[PlanetCNC]

Maximum recommended value for encoder is 100 PPR.

TNG also supports compensation for Z signal if reduction is used.