Long-term tests of some inexpensive barometers and results of pressure cycling of an AIR-DB-1A

Abstract

For approximately 1.5 year, daily observations of barometrc pressure were made with a varety of sensors and compared to readings from a Paroscientific Model 760-16B while all sensors were maintained at a temperature of 20°C±2°C. The results of two samples from each of three inexpensive (strain gauge integral to a silicon chip) pressure sensors are reported on. The SenSym Model SCXI5AN, Nova PI and the Microswitch Model 134PC15A1 had standard deviations of 0.2, 2.6, and 5.6 mb, respectively. The SenSym and Nova sensors had drift rates of 0.5 and 0.9 mb per year, respectively. A fourth sensor, the Microswitch, had output that was too noisy for a meaningful computation of drift rate. Neither of the Omega Model PX93-015GV samples operated properly. The excellent results indicate that strain gauge sensors are worth considering for measuring barometrc pressure in situations where the highest accuracy is not required. Temperature effects, which can be substantial in strain gauge sensors, were not investigated. Pressure cycling tests of an AIR Model DB-1A show that cycles of 3-10 psi above ambient pressure do not affect the accuracy of the sensor, even after millions of cycles. Therefore, rough weather conditions at sea, i.e., waves washing over the barometer port on a drifting buoy, are unlikely to cause inaccuracy in an AIR sensor.