AGA calculations and software certification

[guilio2010]

I know some PLC already contain routines that calculate gas flows according to AGA 3, 8, etc... Everything I am reading on certification deals with the device that is measuring but the software to do the measurement must follow the AGA standard calculations. So the question I have is if I use a meter to get static, diff, and temp, and that meter is certified for use for gas measurement, could I develope a program for a PLC/PAC as long as it followed the AGA guidelines to caculate the gas flow? Does that program have to be certified?

Thanks,

 

[kinser06]

If your doing some kind of custody transfer then i would say that yes the program would have to be certified. A typical AGA8 block that i'm used to using comes in a library with my Modicon M340, the AGA8 block is already certified. I'm using ultra sonic meters so for that particular function block you would need gas velocity, pressure, temperature and also gas chromatograph data to satisfy the super compressibility portion of the equation.

 

[danw2]

I'm curious. Who certifies a function block?

 

[kinser06]

I apologize i didn't mean the function block needed to be per say "certified" (as Dan pointed out i don't think that would be feasible), as long as it abides buy the AGA8 standard calcs then you logic is fine. A meter that only measures static, diff and temp would not satisfy the AGA8 requirements though.