We've been noticing that when an Omron 2SMPP-022SMPP-02 sensor is put under even a very small pressure the reading goes down over time We've checked for leaks in the system and ruled those out We know the reading is very stable at zero pressure Our application is a water level sensor The tube is 10 feet long 1/4 inch diameter so the exposure of the air in the tube to water is fairly low although even at room temp you would expect some water vapor pressure to be present The question we have is whether the reduction in pressure reading from the MEMs sensor is due to the water vapor building up or is it due to something else we are not considering We do have a temperature sensor and are ruling out all temperature related effects The pressures we operate under are only about 2 to 10 kPA The sensor is rated at 37 kPA Data on sensors is not clear on affects of small amounts of water vapor
