We were probably among some of the first users of the ADIS16209 inclinometer chip. We have about fifty of them installed inside environmental chambers which are embedded in a glacier, and have been monitoring them for two years now. We see a systematic drift in the X and Y tilts. I can't eliminate the possibility that this drift is real (since I no longer have direct access to the devices) but it seems unlikely. We see 1) a tendency for both X and Y to always decrease in real value over time (positive values become less positive and negative values become more negative; timescale is several months) and 2) This decrease is considerably more pronounced in the Y channel.
Has anyone else seen this behavior?
Thanks in advance for your help.