Suppose you wish to calibrate a pneumatic pressure transmitter to an input range of 0 to 200 inches of water, with an output range of 3 to 15 PSI.
Complete the following calibration table showing the test pressures to use and the allowable low/high output signals for a calibrated tolerance of +/- 0.5% (of span):
Suppose this transmitter is installed as part of a complete pressure measurement system (transmitter plus remote indicator and associated components), and the entire measurement system has been calibrated within the specified tolerance (± 0.5%) from beginning to end.
If the operator happens to read a process pressure of 153 inches W.C. at the indicator, how far off might the actual process pressure be from this indicated value?
Answer:
Given the tolerance of ± 0.5% of the 200” span (± 1”), the actual process pressure could be as low as 152 ”W.C. or as high as 154 ”W.C.