Programming Help: how to read first value

[1uan]

I am using a NavX IMU board for our robot this year and I want the first value that the navx reads when the sub-vi is executed to become the set point in the PID function and the other values from the navx to be the process variable in the PID function. currently i have a button to set the set point value but i want the sub-vi to do this automatically. The Subvi takes the yaw value of the Navx and uses it to hold heading.


Any help is appreciated.