Balance calibration

balance calibration in which guidelines ?

Pharma industry standards need to undergo 3 principles to achieve high quality

FDA/EMEA\GMP\ISO state that manufacturers must maintain calibration records.
In there documentation is mentioned that is utmost important and it is required.

I do not know which part of all the documentations, since there are many.
But simply said all equipment which measure (balance, sensors etc) need to be calibrated.