I’m looking to install a water meter with hall sensor pulse output to connect to my OS 3.0. What’s the recommended pulse frequency? I see options from 0.25L per pulse, 1L per pulse (common) up to 10L per pulse or even more.
The numbers you are referring to here are ‘pulse rate’, they are not pulse frequency. You can get a rough idea of pulse frequency if you know your water pipe’s flow rate (i.e. how many liters per second). The flow rate divided by pulse rate is the number of clicks per second.
For example, if you choose the 1L/pulse version, and your flow rate is roughly 5 liters per second, then while water is running it will generate roughly 5 pulse per second. I think anything below 10 pulses per second is ok — if the frequency is much higher beyond that, the controller may miss some clicks and consequently the flow reading may be inaccurate.