Lim Sew Hyong

Zstar3 sensor PC application: calibration

Discussion created by Lim Sew Hyong on Jul 6, 2012



I have a MMA7455L sensor board and USB stick. I am developing c# PC application with zstarlib.dll and I never change the software of the MMA7455L sensor board.


After AutoCalibrateAll() is called from PC side, I don't understand why the X and Y axis are calibrated to 0g, but Z-axis is calibrated to 1g?




When I received the sensor real acceleration data through USB Stick, do I need to re-calculate the Z data like explained in AN3447?


For the Simple 0g X, 0g Y, +1g Z calibration technique a slightly different calculation is required for the Z axis which has recorded the CZOFF value at +1g. The sensitivity ‘S’ must therefore be subtracted from CZOFF in the calculation.

For the Z Case:
            AMEAS = [CA- (CZOFF-S)] ⁄ S


Please advice.

Thank you.


Best Regards,