IMU2 Temperature / Compensation Question

ArduCopter Copter 3.6
1

We were having a problem with the Gyros Inconsistent Pre Arm message, and when looking through logs I noticed that on multiple craft the IMU2.T (temperature) value was always zero. IMU1 and IMU3 had temperatures that made sense.

I can also see that the IMU2 gyro values drift as the internal heater brings the board up to temperature, while IMU1 and IMU3 do not. This makes sense given that the temperature value for IMU2 is always 0 - it can’t perform any temperature compensation on that sensor, hence the drift.

This seems to be consistent across multiple PixHawks.

So is this normal behavior? And if it is, what is the reasoning behind it?

Thanks in advance.

2

Hi whopis,
I am having exact same issue and that was the exact conclusion that came to mind.
I read that the IMU2 is near IMU1, so it doesn`t need a separate TMP sensor, but I guess the compensation is not aware that T2 is always 0.

The Gyro 2 seems to follow the Temperature curve (from IMU1) exactly.