Hi there, I am doing some measurement using an accelerometer. I am rather confused with regards to whether I should be see an accelerometer as a non-inertial or an inertial sensor. I have with me 2 commercial accelerometers evaluation board (analog to computer interface). One by the analog/crossbow collaboration board tells the static g as a +1g value, which is seen as a non-inertial reference frame whereas the other one by ST microelectronics with some third party tell static g as -1 (the inertial ref. frame). Both of them tells positive acceleration swing from a positive axis acceleration and vice versa (this is okay). Say now if I am interested to tell if I should be considering the centrifugal acceleration (I am mounting the accelerometer to a pendulem). Should I be taking the centrifugal acceleration as a non inertial or an inertial one? I am assuming that based on the fact that (Both of them tells positive acceleration swing from a positive axis acceleration and vice versa (this is okay).), I will be seeing a negative centrifugal acceleration (given positive direction to skyward). So I will not be able to see a non inertial centrifugal centrifugal accleration? Hope to hear from you guys.