How can I measure Duty cycle ?

[skimask]

Hello friends ,

I`m trying measure my cars injectors duty cycle .
Have any body experince about this ?

For example ,
injectors running pwm cycle ,
if injectors full open ,I must see %100 duty cycle on the display.

Im trying measure injectors cycle (ms) than calculate duty ,
but this is not correct way I think .

This kit ,
http://www.jaycar.com.au/productView...=&SUBCATID=347

working great ,They are use a 16F84 pic only .

thanks

PBP...
Use the Pulsin twice; once to measure the pulse width when low, then right after that, measure the pulse width when high. Add the two results together. Multiply the total result by 100 and divide that total by the pulse-high result and you'll get a percentage relating to a duty cycle. This will get you close, but not absolutely perfect. The total pulse width could change a lot between successive readings (i.e. during fast acceleration or deceleration) and completely ruin the end result. Maybe a little bit of software filtering or averaging over a couple of cycles added to the software.
JDG