I am working on pressure control of nitrogen compressor on 99 psi, Feed back control with MPX5999D and PIC18F4620, have problem that after few day's reading of ADC is down to 0. Pressure sensor found no output at 4.7 VDC supply at any pressure.
Hello Rajendra,
Unfortunately our pressure sensors are qualified for clean dry air only. Most probably the MPX5999D is already damaged due to direct exposure to other media.
I would highly recommend you to take a look at the following thread, where I explain how to protect our devices:
https://community.freescale.com/docs/DOC-102585
You can find this thread useful too:
https://community.freescale.com/message/367452#367452
Hope it helps.
-Josh