Mastering at a Non-zero position - R30iA Controller Fanuc

They are the mastering. They relate the encoder count to the mastered position.

When you purchase a new robot you have to enter them in.

If the relationship changes then they are no longer valid. But if not they can be used to remaster.

The counts stay the same unless you change them either manually or by mastering. They don't automatically change.

If the encoder relationship changes then you will remaster and end up with new values.

Quote from alive15

Okay, so what are the master counts and what do I use them for?

Before the addition of single axis quick master, the counts could be used to revert axis' unintentionally quick mastered back to their proper values. Any more, I don't find myself ever using them.