MPU6050 - invalid readings of the z-axis

Using Arduino Sensors
#1

Hi,
I recently bought an arudion uno and few sensors for my project and I have problem with one of these: MPU6050.

I downloaded library for this sensor from http://www.i2cdevlib.com and uploaded sketch with demonstrates dmp usage.
Link to the sketch: https://github.com/jrowberg/i2cdevlib/blob/master/Arduino/MPU6050/Examples/MPU6050_DMP6/MPU6050_DMP6.ino

When I uncommented OUTPUT_READABLE_REALACCEL and tried to get acceleration without gravity I got strange values from z-axis. It's look like that after ~10s x and y axes show values around 0 (expected) but z-axis never zeroes. I checked code of this library and it seems that all 3 axes are caluclated the same way. I also tried different MPU6050 unit (from the same vendor) and it behaves the same. Any suggestion what can be wrong?

#2

Earth gravity.

The accelerometer should have about 1g for the earth gravity.

#3

I assume that functions used in this example removes component of the gravity form x, y and z axes (completly). In such case if sensor doesn't accelarate values should be similar to 0.

#4

I've been having the same problem since I got the chip in February. I get a consistent reading of around +1700 at rest on the Z axis, which doesn't correspond to anything that I'm aware of (gravity would be ~8000 when using the 2G scale, correct?). I posed a question to Jeff Rowenberg on the only forum I could find that he participated in but didn't get a response.

Would love to figure this out. Too late for a refund if it's a chip error but I doubt it is.

#5