We are working on a skeleton framework to integrate PV inverters using a Modbus TCP connection, starting with a Growatt Mod-type inverter. Monitoring works flawlessly when using a virtual device. The skeleton can be easily adapted to other PV inverters, as long as they support a Modbus TCP interface—just check the required Modbus registers, and you’re good to go.
Currently, we’re figuring out how to get the control functionality working. Our thoughts so far:
Control options:
Via Modbus register (TCP: 0–255 steps), or
Via RRCR (4-wire, 5-step control)
Parameters to check:
Battery full and feed-in disabled → set power to zero
Battery full, feed-in enabled, and negative tariffs (via VRM API) → set power to zero
Exceeding the power limit of a MultiPlus → reduce power
Exceeding the current limit → reduce power
Possibly something based on voltage?
Anyone have more ideas?