ModbusInMqtt Protocol#

Communication protocol between GbbOptimizer and GbbConnect2 — transferring Modbus commands over MQTT.

GbbOptimizer → GbbConnect2#

PUB {PlantId}/ModbusInMqtt/toDevice

Modbus commands sent to GbbConnect2

Field		Type	Required	Description
`OrderId`		string	no	Text copied to the response
`Lines`		array	yes
	`LineNo`	int	yes	Line number
	`Tag`	string	no	Arbitrary text copied to the response
	`Timestamp`	int	no	Unix UTC time (seconds)
	`Modbus`	string	yes	Modbus command to be sent to the inverter
`LogLevel`		string	no	Change log level: `OnlyErrors`, `Min`, `Max`
`SendLastLog`		int	no	1 = attach logs to response (incrementally)

Example:

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{
  "Lines": [
    {"LineNo": 0, "Timestamp": 1746136816, "Modbus": "010300D6000225F3"},
    {"LineNo": 1, "Timestamp": 1746136816, "Modbus": "0103020800024471"}
  ],
  "OrderId": "f0PGI3obQIZTs8w="
}

GbbConnect2 → GbbOptimizer#

Field		Type	Required	Description
`OrderId`		string	no	Copied from the request
`Error`		string	yes	`"OK"` or error description (not related to a specific line)
`Lines`		array	yes
	`LineNo`	int	yes	Line number
	`Tag`	string	no	Copied from the request
	`Timestamp`	int	no	Unix UTC time
	`Modbus`	string	yes	Modbus response from the inverter (empty after the first error)
	`Error`	string	no	Empty = OK. Filled = error during communication with inverter
`GbbVersion`		string	no	GbbConnect version
`GbbEnvironment`		string	no	Environment: Windows, Console, Library
`LastLog`		string	no	Logs since last send (if `SendLastLog=1`)