Do I need to calibrate the control systems that are in service?

No. You simply need to check that the control systems are stable over time in order to make sure that the instrument is accurate.

TheFrenchCollege of Metrology has published a document entitled "Surveillance des Processus de Mesure, Ou comment garantir au quotidien la performance des processus de mesure" (Monitoring measurement processes, or how to guarantee the performance of measurement processes).