Modbus Lonworks compatibility


Thread Starter


Hello All,

I have been struggling with this project for a while now, and you guys are my last resort.

I have to connect 160 M-Bus Abb Power meters to a Lonworks PLC. My colleagues came up a few times ago with this configuration :

Power meter communicates (M-bus) with M-bus/Modbus convertor which sends the information to RS485 serial interface to a Lonworks PLC.

I have the power meters addresses which I can introduce in the M-bus/Modbus convertor (Adfweb hd67022m-80) but the convertor driver asks for modbus registers to assign to every power meter.

The question is where should I write the data from the power meters. Are the Modbus registers compatible with Lonworks?

Thanks you for your help!

You will need to specify the Modbus RTU registers to be used, then you will have to convert Modbus RTU to LonWorks as they are physically very different networks, or use as they can go from M-Bus to LonWorks.


Yes, you need connect the M-Bus parameters to Modbus registers or you can use the M-Bus protocol without the converter (you need hardware converter between M-Bus and serial port). Then the parameters read from M-Bus device must be connected to the Lonwork network variables. You can use the Mini FX evalution kit ( It has serial port so you can poll the M-Bus device and then store the values in Lonwork network variables.

Loytec has devices with a built in DPAL layer that allow you to easily pass Modbus, LON, and Mbus between each other. These devices also have a built in OPC Server so you can make any of that protocol data an OPC tag.

The modbus capability is very nice (seriously its Modbus so it only gets so nice) with built in scanner and analyzer and ability for you to make custom register types (for passing to different technologies).

And, you can get the device in PLC format. It uses IEC61131, down to 10ms cycle timing with hundreds of hot swappable direct and remote I/O.

Another note- it has BAS functions so it also has a webserver with email and AST (alarm schedule trend) built into the device.

LINX Automation Server or LGATE-950 is what to look at from their site.
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