What’s the maximum cable length that can be used with a 3 wire flow sensor attached to an Open Sprinkler controller? I know this is dependant on the flow sensor requirements and how much current the 5V pad can supply but I want to get a general sense of the length from people who are using these with Open Sprinkler before I buy it. 2 wire dry contact ones for irrigation go relatively long distances (at least a hundred feet or more) but are really expensive. If (with the right sensor and wire size) I could go a similar distance with a 3 wire sensor and Open Sprinkler that would fantastic.
I use Cat5 twisted pair cable to connect 3-wire (Hall effect) flow sensors to my wireless pulse transmitters. Cables are not wired into opensprinkler controller at all, although there are sensor connectors for that purpose. I prefer my pulse/flow data to be monitored on separate cloud server. Wireless pulse transmitters also need their own DC battery (CR2032). Longterm battery life is the biggest issue with me, as I won’t get data once they are weak and need replacing.
I keep opensprinkler for the simple function of turning on solenoids in field only. No batteries, just standard 24vac and 5v for its wireless function.
OTOH for watering data, I use DC batteries on flow sensors at end of run, to supply pulse output, usually near pulse transmitter, mainly to keep battery connections away from flow sensors which tend to operate in wetter environments.
Cheaper 2-wire alarm signal alarm cable would also work in place of Cat5/Cat6, which is usually 22-24 gauge.
Attenuation of signal for cat5 limits cable runs to 100m/300ft. So the digital pulse signal from flow sensor may degrade after that distance without some kind of signal booster or amplifier.
I should mention that the specs. for Hunter Flow-Sync sensor say a maximum of 1000ft/300m from the (Hunter) controller when installed with 18AWG or 1mm gauge or larger copper wire. That suggests you should use larger diameter wire for runs greater than 1000ft.