Q: As time passes after cal, the cal data changes little by little.
A: Under the precondition that cal is normal, checks whether the little changes in value is constant.
If it is constant, check the cable connection or replace the cable with more expensive and better specification (Flexibility) cable.
Q: Because it is a school, the side of the pad is large enough to be seen, so tip contact is easy, but measurement is difficult.
A: Isn't the pad large, but the thickness is thin? When the thickness of the film is thin and the tip is thick, accurate contact may be difficult.
Vibration removal and accuracy of tip contact are required.