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Why i am not receiving a constant values?

Anil3
Associate III

Hello everyone!!!!

I am using Motion_FX (9 axis) library in my application and receiving the values of Yaw, Pitch, Roll and Heading but these values, which i am receiving are not constant even if i kept the sensor in a fixed position values are varying with +/- 5deg for example if we consider heading values and rotate the sensor board to 90deg and kept it fixed for that position then i am receiving values like 89.78, 87.82, 86.43, 90.12, 90.12., 91.56, 93.75 like that...i am not getting a fixed value of 90 deg...how can i get fixed values...

Awaiting for your valuable reply,

Thank you!

3 REPLIES 3
Petr S
ST Employee

Hello Anil,

I don't have the same issue on my HW. Can you please send me your datalog so that I can replicate the issue on my side? Please make sure it contains time stamp, all 3 axes from accelerometer, gyroscope and magnetic sensor and your calculated output values for each input values record. In the attachment you can the example of data format that I can easily work with.

Thanks and regards,

Petr

Hello Petr,

Thanks for your reply,

In my application i am using 2 sensors 1) ISM330DLC 2) ISM303DAC, as there are 2 sensors, i am reading the values of both sensors separately. and giving those values to Motion_FX library and using 9 axis...

I am not using any timer in my application...will it cause any effect on output values? and also i will share the data of logs to you in short.

Thank you!

with regards,

ANIL.

Petr S
ST Employee

Well, there must be some delta time you provide to MotionFX library (float *eml_deltatime) in MotionFX_update and MotionFX_propagate functions. It must be REAL delta time between two samples otherwise it doesn't have to work correctly. So please add this value to the datalog you plan to send me. You can use DataLogFusion application in X-CUBE-MEMS1 and MotionFX user manual as a reference.