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

[kazkibergetic]

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

Sounds good, thank you.

>>>Could you provide the test procedure, device and the environment?

We calibrate all sensors on the same stand. We use TPI A9012 accelerometer, another device with analogue MEMS and our device with BMA490L. First to accelerometers give a result close to each other, our device with BMA490L gave us higher values. 

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

>>>If you keep sensors static, and the values of accel is same, x/y/z nearly 0,0,1 g.
yes, all six-axis give us values close to  1 or -1 in one axis and close to 0 in the other two. 

>>>If your change sensor position, such as x-axis perpendicular to the earth, x/y/z nearly 1,0,0?
correct

>>>While, if your move sensor with 4g accel, sensor's output is different, nearly 10%-20% difference?
yes, compared to what we used before (TPI A9012 accelerometer and another device with analogue MEMS)

[Yanchao · Accepted solution]

Hi,

Normally, BMA490 sensitivity error couldn't beyond 10%, I'll check this value and feedback to you. Meanwhile, have you compare 3~5 bma490l g-value output, or just use one bma490l make test?

BMA490 config: odr? range? normal mode?

More info from your test enviroment/procedure.

• How do you generate accel apply on BMA490l and A9012? What's the real accel value?
• As attached photo, the relation X/Y/Z with Main g? Angle/Phase?
• BMA490L and A9012 test at same time and postion?
• Could you upload BMA490L and A9012 log data before/after your test?