Precise control of a thermal system requires time, care, and expense. Highly sensitive measuring instruments and indicators, as well as frequent recalibration in service, are required to know how good the control is. One basic question of a user of a thermal system is whether the temperature control is accurate enough to produce a product or operate a process satisfactorily? Eliminating the last degree or fraction of a degree of temperature deviation is costly and should be done only for sound practical reasons. Good temperature control can be achieved using standard instruments.
System bandwidth and constancy of mean temperature are the overall measures of control accuracy. They are affected by many factors including: