My calibration sphere is fixed at a point. But whenever I qualify a new probe and select no change in movement of sphere, the value of x y and z of Sphere always is different from nominal
Are you sure you don't mean the xyz of the tip you have just measured ? You have nominals for tip and actuals as long as you StdDev is within 0.005mm you are ok.
Your machine conducts a "home" every time it is restarted. That effort of "Homing" is via magnetic hall sensors, which detect the magnetic field of a physical magnet stuck to each axis. It's relative accuracy & reproducibility is crap. I don't know why Hexagon is still depending on this methodology, considering they've got readheads right effin there. --In any case, each time you home the CMM, the machine's volumetric origin shifts (i've seen upwards of 1/4" in each axis). Hence why your cal sphere "moves".
Technically, E.V.E.R.Y. EVERY EVERY SINGLE TIME your machine gets restarted and conducts a HOME move at startup, you are supposed to update the MASTER PROBE by calibrating it and saying YES to the prompt. In fact, if you read between the line of that whole caution prompt, it queries if the "machine's zero point changed"
--Which is asking "has the machine conducted a Home since last master probe Yes command?" if so click YES.
