I'm trying to measure water pressure of water pipe by exactly replicating this : http://www.practicalarduino.com/projects/water-tank-depth-sensor
When I tested the sensor (by leaving both inlet free, and printed the result directly to Arduino's Serial), I got a wave-like output. The sensor gave high output (1023) then steadily dropped to 0, and then increased again.
I've also tried to test the sensor by directing both output (+Vout and -Vout) to Arduino's analog pin. And the result stayed the same.
My question is: Is this condition normal? I have no experience before with pressure sensor so I have no idea if this is working correctly or not.
PS: I've tried the component by using 9V adaptor. From the datasheet (http://www.nxp.com/files/sensors/doc/data_sheet/MPX2010.pdf) I found that
Vs = 10 Vdc
While Vs = supply voltage, what does Vdc stands for? And what's the difference it has with Vs?
Update : I found this https://stackoverflow.com/questions/2851078/analog-readings-on-arduino-returns-wrong-values and it seems the case is almost similar to me. Should I do the same with my MPX2010 from the output pin (even though MPX2010 already had its own ground from the 1st pin)?