Thank you for taking on this topic and working getting Kostal implementation and throttling to work.
Here are my comments and observations.
As it already has been pointed out Kostal by default uses Modbus Port 1502 (not changeable) and unit ID 71 (changeable via Modbus or some API implementations i.e. Kostal IoBroker ).
I am Using a Plenticore 10 Plus Gen2.
I Changed the unitID to 126 via iObroker.
I also created an SSH Tunnel to redirect Port 1502 to 502 (quick and dirty like ssh root@localhost -L *:502:IP.OF.PLENTICORE.DEVICE:1502)
I then added the inverter manually.
It does show up! I also enabled power limitation support and did set a limit in ESS settings.
On the inverter screen I could see the limit being changed. However it never changed on the plenticore device.
I also tested if the Plenticore Plus supports setting the limit via Sunspec.
It does! I did the test with the iOBroker modbus adapter.
According to the documentation Kostal provided. Holding Register 832 is used to control the active power output limit. Somehow VenusOS is not able to limit.
I would suggest to enhance the inverter screen to add custom ports and unit IDs to give the follks that use Kostal devices an opportunity to test.
To me it looks very promising.
Here we can see the limiting calculation works..
and changes.
But newer gets into the Plenticore device.
