BMA490L shows g-values that are to high

[kazkibergetic]

Hello,

We are using BMA490L in our equipment (sensors).

1) We decided to compare the g-values provided by our sensor with other sensors (different accelerometer).  BMA490L gave us numbers that are 10-20% higher than other sensors (for example, 3.7g vs 4.3g). We are not sure what could be the reason. Calibration seems to be fine, we are getting 1g, -1g. 

2) Another thing we noticed that each sensor has a different sampling frequency (we set it to 800Hz but getting 790-815Hz depending on the sensor). Is it normal?

I really appreciate any help. Thank you. 

BMA490L pins connection: 

Pin 1 (SDO) ---- GND

Pin 4 (ASDA) ---- GND

Pin 6 (INT2) ---- GND

Pin 10 (CSB) ---- 3V3A 

Pin 11 (ASCL) ---- 3V3A

[Yanchao]

Hi,

Q1:compare g-values

Have you make accel offset compensation? If you finished compensation, accel x/y axis value nearly 0 mg, z axis nearly 1 g. So 10-20% higher than other sensors really unbeliveable.

Q2:sampling frequency with different sensor samples

I'll check internal and feedback to you ASAS.

Best regrads.

[kazkibergetic]

Thank you for your prompt reply.

With regards to the g-values, I am surprised as well and have no idea what could be the reason. Here you can see measurements done with different sensors, the left one is using BMA490L. Offsets seem correct, I am getting closed to 0,0,1 when sensors are not moving. Any help is appreciated. 

[Yanchao]

Sorry, I still don't understand. Could you provide the test procedure, device and the enviroment?

In photos, BMA490L x-axis 3.89, y-axis 3.95, z-axis is 0.06, the unit is g?

If you keep sensors static, and the values of accel is same, x/y/z nearly 0,0,1 g. If your change sensor position, such as x-axis perpendicular to the earth, x/y/z nearly 1,0,0?

While, if your move sensor with 4g accel, sensor's output is different, nearly 10%-20% difference?

[Yanchao · Accepted solution]

Hi

For ODR accuaracy, our test data as bellow. And your test data in range of our test result.

Normal mode: 2% ~3%

Low power mode : will be little worse . let's see feedback from customers.

Best regrads.