I have to test an application which is very dependent on a vessel pressurized with air to 30psi leaking less than 0.01psi over 1 minute. Thus, I'm trying to figure out a way to read psi down to 0.005psi. I'm working with a 0-75psi/0-5V analog pressure transducer. I have verified with a high-quality DMM that the transducer can communicate changes down to 0.005psi effectively. However, I need to make a report of the seal leakage data, and I'd like to collect the data using Arduino.
Having a 10-bit ADC suggests that, to get an accuracy of 0.005psi, the full scale I'm working with needs to be 0.341psi. However, I need to test this seal at 30psi. To maintain this full scale psi, I should be able to guarantee an input of 30+/-0.170psi.
So here' my question. Is it possible to somehow divide the output of my analog pressure transducer such that a 1.989-2.011V output from the transducer turns into a 0-5V input to the Arduino ADC? Again, I'm measuring changes, so a voltage input to the Arduino does not need to accurately correspond to an absolute pressure in the vessel. In addition, would the method be safe for inputs outside the 30+/-0.170psi range (such as when the vessel is being filled)?