Why Control Precision Matters

Document(s): 

Why Control Precision Matters (1.65 MB)

Pressure controller/calibrators are used to calibrate pneumatic process measurement instruments or field calibration devices. Although these instruments generally include control hardware and a precision transfer pressure standard (transducer), they often are referred to simply as “pressure controllers” since they are normally used to deliver a controlled pressure to the unit under test (UUT), at which the nominal controller set point and/or the reference pressure transducer’s measurement can be compared to the measurement of the UUT.

The performance of pressure controller/calibrators is most often compared based on the measurement precision and uncertainty characteristics of the reference pressure transducers used in the calibrator. Another important performance specification, which is reported but sometimes underemphasized, is the calibrator’s control precision. Control precision has an impact on the calibration accuracy realized by the user. As shown in this application note, control errors can become as significant as the measurement uncertainty in some cases. The importance of control precision is increasing with the recent trend for covering multiple pressure.