This comprehensively updated EEMUA Code of Practice provides a guide to the principles and methods used for calibrating and validating process (on-line) analysers. EEMUA 175 provides detailed guidance on continued validation (in-service checking) and any required calibration adjustment, including the use of control charts. The publication is based on and supersedes the IP Codes 340/82, 341/82, 347/82, 348/82, 349/82 and 353/82.