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I have RUT955 with firmware version RUT9_R_00.07.01.2. Currently I am trying to integrate the RS485 based energy meter with this device. I successfully getting meter register data into modbus serial master module in internal server. Herewith, I attached screenshot.

Now I want to send response of same query through MQTT broker. For that I enabled MQTT borker and try to set parameter in Data to server but i am not getting proper idea to set json string.

Can any one help me?


May i ask for what purpose you are trying to read a meter? Also, are you wired up for 3 wire (+,-,com) or 5 pin (+,+,-,-,com)?

I've tried to connect to a meter using 3 wire method where you jump the + to the + and the - to the - to make two inputs and the ground as the com.

May be i'm doing it wrong?

You will want to use data to server method to extract data.

I use {"ts":%t, "values":{"%r":%a}}

although there is a firmware bug in the rut955 which misses out a ] at the end of the json, making it invalid anyway.

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I do apologize for a late reply.

I would like to check whether I understood correctly, you are trying to send Modbus data using Data To Server via MQTT protocol? If so, you wouldn't need to enable MQTT broker, all you would need to do is configure Modbus Master(which you have already done I believe) and configure Data To Server service.

To do so, navigate to Services -> Data To Server and configure as follows:

Please note, that the I have put the default Json string, you can add or remove options depending on your application. In addition, it is important where exactly you are trying to the send this data via MQTT, you would need indicate either an URL or a connection String(If for example, you are sending the data to Azure IoT Hub).

More on Data To Server:

Note: If you would need further assistance, Could you please elaborate exactly where you want to send this data with Data To Server and what exactly functionality you are trying to achieve, because MQTT Broker and Data To Server are two completely different services unrelated with each other.(They only use the same MQTT protocol)

Best Regards,

Dziugas K.

Hello sir,

Actually my energy meter is connected through modbus. I want to sent first query on modbus register and whatever reading I get will send to server.

For modbus query, my slave ID is 1, function code is 3, register address 3040, and register count is 2. My string is like 01 03 0B DF 00 02 F7 D5. Now whatever result of this command send to server through mqtt.

I don't know how to set json string for my modbus query. I already set it in modbus master and getting data properly.

Hello again,

Could you please download the troubleshoot file and forward it to me via private message. In order to download the troubleshoot file, please navigate to System -> Administration -> Troubleshoot -> Download Troubleshoot

More information on where to find it:

Best Regards,

Dziugas K.