The most reliable method to test the sensor system is to inject a known concentration of test gas, as during calibration, and observe the reading and alarms.
In all analyzer systems, there is a possibility of undetected faults which might disable the analyzer's safety function. Therefore the greater the frequency of calibration and test, the lower the probability of an undetected analyzer fault.
Automated test and calibration features in computer-based analyzer systems economically allow increased frequency of calibration and test, increasing reliability.
However, a note of caution is needed: Automated systems add reliability, but are not valid substitutes for proper training and awareness of the operator.
The operator who is familiar with the basic principles of solvent drying and the function of the analyzer is in a unique position to detect abnormally high or low solvent concentration readings which may be due to a fault in the process or analyzer that should be immediately investigated and corrected.