| Popis: |
The problem of instrumenting a large cryogenic tank for accurate temperature measurements is classic in the aerospace industry. It generally turns out that the primary sensors can be the same for both large field installations and small laboratory tanks, but the resemblance ends at the tank wiring interface with the readout circuitry. The laboratory researcher attaches manually operated switching and Potentiometriv readout devices to his small tank, while the aerospace research engineer must operate at the end of a long instrumentation line, typically 500 to 1000 ft, with automatic data-logging equipment. The laboratory researcher can hover over his system, taking great pains with all aspects of the data-taking process, so that he has a good “feel” for the accuracy of his data. The aerospace research engineer, on the other hand, usually deals rather remotely with his system, writing specifications in such a way that the test will yield data to the level of accuracy he desires. As often as not, he is absent from the test blockhouse during the test procedure, thus lessening the effectivity of his personal control. |
