How to adjust the frequency of receiving imu in pixhawk?

Sorry, I am a newbie who just touched pixhawk.
I want to receive 100hz or 200hz via pixhawk.
Thank you for your advice.

Not sure what your question is, but you should be able to find the answer in the docs here: http://ardupilot.org/copter/docs/introduction.html#introduction

I can receive IMU data in 25hz via pixhawk and store data in SD card , however,I want the imu information is to update in 100hz.
thank you for your advice

thank you for your link !!
I solve my problem.

Great! I’m glad the documentation helped.

how did you do it?
and were are you logging?

I just tuning parameter list like log_disarmed and LOG_BITMASK.
Make sure I can always receive data in SD card and receive the frequency I want .
I am just lucky to tune to the 100hz I want.
I am also finding another way to tune any hz in IMU data .

How did you do to change the frequency of the imu