sioc script for tach

I am working on writing a script for my servos card to drive a tach. below is what I have so far, I copied it and modified it from the info OC supplied. I don't know how to program the internal variables, L1, L2, and so on. I want to learn how to do this on my own. The script is valid but does not react to fsx correctly. Are there any scripts that I could refer to, or any reading that might help? Glenn

I just did some testing and found out I can directly drive the air core gauge I have for the tach off the pwm signal from the usb card. I removed a dropping resistor in the gauge and it works fine to full scale, real stable. I plan to do that instead of converting the needle to a servo. Why do work you don't have to? :)