Encoder Noise

I would try first setting the muxed-encoder.sample-frequency to say
2000000 (2 MHz)

Beware that this will limit the maxim count rate on all encoder channels
with filter enabled to about 250 KHz, so make sure you have reasonable
following error settings as you could get a runaway

If you have higher speed channels, and this is too slow, you can turn off the
filter bits on those channels

Did you have an example? Is it set in hal file?
frequency on this channel in rapid feed is 1.8Khz. Z-Axis is maybe near 20Khz so should be not problem to degrease frequency

i found one old fanuc encoder cable and soldering in for test. it seems poor quality of cable is the problem. Now level not change but no noise. And this grounding is magic. First picture is not grounded and second is grounded. So if i ground this encoder cable the noise increase?

PCW wrote:

I would try first setting the muxed-encoder.sample-frequency to say
2000000 (2 MHz)

Beware that this will limit the maxim count rate on all encoder channels
with filter enabled to about 250 KHz, so make sure you have reasonable
following error settings as you could get a runaway

If you have higher speed channels, and this is too slow, you can turn off the
filter bits on those channels

I found the pin and set frequency
setp hm2_7i76e.0.encoder.muxed-sample-frequency 2000000

For z-Axis switch off filter by
setp hm2_7i76e.0.encoder.00.filter 0
i will observ if axis shift...
If someone has 10m encoder cable to sold let me know.

I found in manual from 7i77
setp hm2_5i25.0.muxed-skew 130
(for 10 ft cable = 100 ns + 3ns per foot)
Symptoms of muxed encoder skew problems are swapped even/odd encoder
channels or noisy encoder channels. For the highest multiplex rate (16 MHz is possible)
the skew may have to be adjusted for the individual 7I77ISOL.

Is the 7i77 maybe an option for noise signals?
And what means muxed-skew?

If you have very fast encoders you may need to adjust for the FPGA --> 7I77
cable length with muxed skew for 2 to 8 MHz sample rate, (default) is not an issue