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sebdehne asked

MQTT/DBUS mapping for MaxChargePower and MaxDischargePower

Hi

How are the mqtt parameters "MaxChargePower" and "MaxDischargePower" mapped to the DBUS?


MaxChargePower: I can find the topic "/settings/0/Settings/CGwacs/MaxDischargePower" in MQTT, but this parameter is not mentioned anywhere in the register excel sheet (https://github.com/victronenergy/dbus_modbustcp/blob/master/CCGX-Modbus-TCP-register-list.xlsx). Does anyone know how to use this parameter from Modbus-TCP?

MaxDischargePower: This one (/settings/0/Settings/CGwacs/MaxDischargePower) works fine via mqtt (both positive number and -1), but via modbus (register 2704), it is not possible to write -1 because the type i uint16. How can I disable to "inverter limit" (which is also shown in cerbo gx) via ModBus-TCP?


Thanks

Multiplus-IIcerbo gxModbus TCP
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1 Answer
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pcurtis answered ·

An easy way to get the D-bus mapping is by running dbus-spy.This has a simple interface which you can navigate with the up, down, left, right keys to explore the system bus destinations at the first level and the paths complete with the real time value returned by GetValue method at the second level. These match the inputs needed for the dbus command and should have a direct relation to the MQTT mapping. Running dbus without the final GetValue or SetValue also seems to give some information on the methods available and types.

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