WHY IS CALIBRATION REQUIRED?
It makes sense that calibration is required for a new instrument. We
want to make sure the instrument is providing accurate indication or
output signal when it is installed. But why can’t we just leave it alone as
long as the instrument is operating properly and continues to provide the
indication we expect?
Instrument error can occur due to a variety of factors: drift,
environment, electrical supply, addition of components to the output
loop, process changes, etc. Since a calibration is performed by comparing
or applying a known signal to the instrument under test, errors are
detected by performing a calibration. An error is the algebraic difference
between the indication and the actual value of the measured variable.
Typical errors that occur include: