With respect to your setup, I have a few comments:
- J1 on the EVAL-ADIS was not intended for connecting to an external processor. While it will probably be OK, there is risk of damaging the EVAL-ADIS's processor and we cannot guarantee that there will no bus contention. For this type of function, we suggest using a breakout board, like the ADIS16IMU1/PCBZ.
http://www.analog.com/en/evaluation/eval-adis16imu1/eb.html - When connecting a DUT, like the ADIS16480, to the EVAL-ADIS, using J1 (intended use of J1), we start to see communication issues when the length of ribbon cable reaches 12 inches. With the style of cabling used in your setup, there could be elevated sensitivity through wider area in the signal return loop. This could be contributing to signal integrity issues on the SPI, which can corrupt the data. It might be hard to investigate a processor overrun with this type of setup.
- What type of material is the apparatus made out of? It would appear to be aluminum or steel. Any local ferrous material can influence the magnetometer behaviors, which have a direct impact on the angles.
- Local wiring and instruments can influence magnetometers as well.
I hope that helps. Thanks again for posting the video.
Best,
NevadaMark