I get a tracking error. the scale of my encoder is correct on my B axis display

Did you check index enable?

To test whether the index hardware is working (assuming you can move the axis past
an index mark), you would:

With LinuxCNC running,  use halshow to watch the signal b-index-enable
and then with either halshow or halcmd, set b-index-enable true"

halcmd sets b-index-enable true

halshow should now show b-index-enable true

now, if you move the axis past an index mark, b-index-enable should go false.

This is how you test for correct index operation.
 

i do that, but never nothing

That points to hardware issues, are you sure:

The index wiring is correct.

The encoders actually have an index output.
 

My wiring is good. I followed the MESA7i96s documentation. I think everything is correct.
I've tested 5 RS-422 encoders with phase A+,A-,B+,B-,Z+,Z-. Or maybe my MESA board isn't working properly. I don't know how to get out of it

if you: 

1. Disconnect the encoder

2. Change the index input to TTL mode
(W1 left)

3. With LinuxCNC running and halshows "Watch" tab showing
    hm2_7i96s.0.encoder.00.input-index, does the state of
    hm2_7i96s.0.encoder.00.input-index change when you ground
    the IDX+ input (TB2 pin 13)?

i will try that tomorow
thanks

So, my signal goes to true, but doesn't return to false once the wire is removed from GND. moreover, it doesn't happen every time. sometimes it works, sometimes it doesn't?

Is the index input jumpered for TTL MODE? (W1 left)

Unless this is done, the results will be unpredictable.
 

I'm doing the test again today

So, when I insert the wire into pin 13, the signal is on “Fasle” and when I remove it, the signal is on “True”. Without connecting Z to GND