congratulations to everyone over the impressive Opensprinkler and great contributions in this forum!
I need your help over the use of the newly introduced flow sensor feature. My irrigation system is powered by two separate water sources, which command different banks of valves, i.e. Source 1 valves 1-20, source 2 valves 21-40, all powered by the same Opensprinkler unit with extensions.
I would like to measure the overall water flow, source 1 + source 2.
What about two different water flow sensors both wired to the only Opensprinkler flow port? Would the measured flow be the sum of the two?
Wiring the two sensor together may work to some extent, assuming that when the flow sensor switch closes it closes for a very short period of time. This is because during the time one switch is closed, it will mask out the other flow sensor. So if the closing time is very short, the total number of pulses you get is still roughly the sum of each sensor. But if the closing time is long, the total number of pulses will be considerably less than the sum. The best way to find out is to use a multimeter to check the conductivity of the flow sensor, and get a sense of how long the switch closes during each pulse.
If they are used alternatively, then it should work fine.
There is a slight possibility that when one flow meter stops it might stop at a closed-switch position, which will interfere with the other flow meter. But the possibility of this is quite small and in practice maybe you will never encounter such issues.