Brewtroller volume readings vary wildly

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May 4, 2019
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I really hope there's an obvious, simple solution to this, but I'm not seeing it and can't find anybody posting anything about it...

After almost 5 years of on again, off again work, I'm finally finishing up my brewtroller system. I was planning on using volume measurement with the MPX5010DP sensors. However, I'm finding that the pressure readings vary wildly at the same volume. For example, when I go to calibrate the HLT volume at, say, 2 gallons, the pressure reading might be anywhere from 28 to 52, which translates to a volume reading of 1-4 gallons. If I add another gallon, the pressure reading is frequently lower than it was at 2 gallons.

To test, I disconnected the wires from the sensors and plugged an external power supply at 3v into the analog inputs on the brewtroller. Even at this steady voltage, with the sensors taken out of consideration, the volume reading varied from about 107 to 114 gallons.

This makes me think the issue is with the controller, but I don't know if the problem is hardware or software. In the volume averaging settings section of config.h, i left it at the default settings of 200ms interval, read count of 5.

Anybody have any ideas or seen this issue before?