I have use this kind of joystick plugged in a Pokeys56U and every time i turn on Mach3 and the pendant, axis moves
I have to open the config and calibrate again the joystick.
When it is in the neutral position I see the volt value continuous variable .
The dead zone is set at 45, less then 40 I have problem

the joystick is this

That is what deadband is meant for. Even 45 is quite a low value.

I have tryied to put deadband at 80, 100 but always the same, axis move by themselves.
Very dangerous when you leave the machine stopped and you see it move alone.
Maybe joysticks in this application are not a good idea.

And when I use joysticks to move head slow, I always receive back an error from UC100 connection

Are you using UC100 or PoKeys to drive the steppers?

no, I use UC100 to connect my laptop (it have not a parallel port) to a control board with the parallel port.
It work very well, I never had a problem.
The parallel board control 4 external driver CW8060

I have also a Contour Shuttlexpress and it work fine, I can control axis and jog with it.

Now i have Pokey56U and I have assembled a Jog pendant