Hello,
reading SMA home manager 2.0 documentation (section 10.4.3 Configuring Limitation of Active Power Feed-In) and connecting moxa device (section 8.3 Connecting Modbus Device Moxa E1214), it appears it is possible for grid operators by means of a ripple control receiver to control the feed-in (grid injection of power) of SMA invertors.
The Moxa E1214 device (i.e. a digital i/o to modbus ethernet device) seems to be the interface between the ripple control reciever, which is connected to a digital input of the Moxa device and SMA HM2, i.e. the moxa exposes the status of the digital input over modbus over ethernet.
In SMA Home Manager 2.0 one can configure the IP address of the Moxa device 'section 11.3.13 Configuring Modbus Interfaces of the HM2 manual).
So I’m assuming that the SMA HM2 polls the moxa device to know the status of the digital input, and act accordingly: e.g. if the digital input D2 of the moxa device is high, the SMA HM2 will limit the feed-in to 60% of the nominal power of the SMA Inverter.
My idea: in order to control the feed-in (injection) in function of the dynamic injection tarrifs, one could “fake” the status of a digital input of the Moxa device.
For this to work Home Assistant could expose said digital input as a slave modbus device on port 502. If the SMA HM 2 then polls the Home Assistant modbus slave interface, Home Assistant could dynamically control the feed-in (i.e. prevent feed-in in periods were injection prices are negative).
There was some work on a Home Assistant modbus slave implementation (cfr Add Modbus TCP Slave support to the modbus integraion by yury-sannikov · Pull Request #47043 · home-assistant/core · GitHub) but was never merged into the code base.
Any ideas on this?
Thanks.
best regards,
Ruben
I’m assuming that