What are the reasons lab measurements can differ from in-line process measurements?
A major reason is the fluids are in fact different under different conditions. This is demonstrated by using calibration fluids. The calibration fluids Cambridge uses have known characteristics that are documented and tied to traceable standards. All Cambridge instruments are factory calibrated with these traceable standards, and the calibration is certified. We note the particular fluids used, their traceability and the results of the calibration. In all cases the factory calibration sheets supplied with each instrument shows the instrument maintains its specified accuracy (1% of the full scale value for the VISCOpro 2000, for instance). Calibration fluids can be used to evaluate process measurements. Specifically, by removing the process instrument from the line and testing it with calibration fluid, it can be compared to the result from a lab instrument using the same fluid. In such a test, both instruments should yield the same result. Unfortunately, process fluids are typically no
