Pulse Flow meter, I get the pulse, how to transform them into Lt/min?

Hallo again,
Robert wall really helped connecting my flow meter, and now I see pulses, the frequency is also right, so that if I stopwatch the interval between two pulses i can calculate flow rate,
But how can I let Emoncms do the work?
I would like to log instantaneous flow rate and pass it over to other processors to calculate cop.
My meter is a pulse flow meter sending 1pulse every 10L, connected to emontx 3.4 wired pulse input,
Please help needed

I’m going to lock this thread, because it is really a continuation of this: