When my irrigation controller runs any zone, a normally open master power 24vac circuit closes (energizes). When all zones complete running, the 24vac circuit opens (deenergizes). I want the open or closed status of that 24vac circuit to control, over WIFI, an existing remote dry contact high amp relay that has a 12vdc coil, that is about 250 feet away, that will turn on the pump. When 24vac is on, the remote 12vdc is on. When 24vac is off, the remote 12vdc is off. Both the irrigation controller and pump locations have strong wifi signals.
What two, or more, Shelly devices can be used in this use case?
I had an RF solution doing this, but the RF receiver component died at the 12vdc coil relay pump side, and I want to switch to wifi. It was only semi-reliable even before it died.
I'm new to this and picking a Shelly device to handle the 24vac on/off trigger portion of this is difficult for me. Is it as simple as using a 24vac sensor that reports on/off status to the wifi app, and, in the app, configuring a remote Shelly 12vdc normally open relay to mimic the on/off status of a 24vac sensor?
Update: after more thought, I think this can be accomplished using 2 relays on the 24vac trigger side. One normally open, dry contact, non-smart (dumb) 24vac coil relay to simply close when 24vac is applied to the coil. Use that as a no-load signal only relay that closes a circuit between S1 and S2 on a smart wifi relay that supports an external switch that senses a closed circuit. Connect smart S1 to dumb N-in and smart S2 to dumb N-out. Connect nothing to (leave unwired) dumb L-in, dumb L-out. Connect smart L-out, and smart N-out to a "running" indicator light for feedback. When the smart relay closes and reports "on" status to app, configure app to mimic on/off status at remote smart relay at pump. Off to finding relays that support that design.
Update 2: I have this working. I used one dumb 24vac signal only normally open relay that closes when 24vac is input. I connected it to a WIFI relay that is normally open that has signal S1 and S2 terminals where this relay closes when continuity is formed between S1 and S2. When this WIFI relay closes, I have the app configured to turn on the pump WIFI outlet. When the WIFI relay opens, the app turns off the pump WIFI outlet.