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.