The post Difference Between Indication of an Instrument and Actual Value of Measured Variable first appeared on the ISA Interchange blog site.
Today’s automation industry quiz question comes from the ISA Certified Control Systems Technician (CCST) program. Certified Control 
System Technicians calibrate, document, troubleshoot, and repair/replace instrumentation for systems that measure and control level, temperature, pressure, flow, and other process variables. Click this link for information about the CCST program. This question is from the Level I study guide, Domain 1, Calibration. Level I represents a professional who has a five-year total of education, training, and/or experience.
The difference between the indication of the instrument and the actual value of the measured variable is:
A) the controlled variable
B) called set point
C) an error in the measuring instrument
D) discarded
E) none of the above
The prompt is very nearly the definition of an error signal-the difference between the indication and the ideal value of the measured signal (set point)-and thus seems familiar. Actually we have a bad meter here.
The correct answer is C.
Source: ISA News
