This project provides a very basic M-Bus end-device to act as a 'slave' role in a wired M-Bus network. It builds on a fork of libmbus and provides enough functionality to:
- Respond to requests
- Respond to primary address scanning
- Respond to secondary address scanning
- Set primary address from secondary address
Note: this slave role device is only used for testing a master.
You can use socat on a Linux system to emulate a point-to-point serial
connection. On one side of the connection you run the mbus-device and
on the other side you can play around with the various libmbus tools.
In terminal A, run socat (as a regular user), take note of the devices
created, /dev/pts/NUM, here we have 12 + 13:
$ socat -d -d pty,rawer pty,rawer
2022/09/26 08:46:54 socat[528933] N PTY is /dev/pts/12
2022/09/26 08:46:54 socat[528933] N PTY is /dev/pts/13
2022/09/26 08:46:54 socat[528933] N starting data transfer loop with FDs [5,5] and [7,7]
In terminal B, start the mbus-device, here we use primary address 5:
$ mbus-device -a 5 /dev/pts/12
In terminal C, start a libmbus tool, here we request data:
$ mbus-serial-request-data /dev/pts/13 5
mbus_frame_print: Dumping M-Bus frame [type 4, 37 bytes]: 68 1F 1F 68 08 05 72 78 56 34 12 24 40 01 07 55 00 00 00 03 13 15 31 00 DA 02 3B 13 01 8B 60 04 37 18 02 1B 16
<?xml version="1.0" encoding="ISO-8859-1"?>
<MBusData>
<SlaveInformation>
<Id>12345678</Id>
<Manufacturer>PAD</Manufacturer>
<Version>1</Version>
<ProductName></ProductName>
<Medium>Water</Medium>
<AccessNumber>85</AccessNumber>
<Status>00</Status>
<Signature>0000</Signature>
</SlaveInformation>
<DataRecord id="0">
<Function>Instantaneous value</Function>
<StorageNumber>0</StorageNumber>
<Unit>Volume (m m^3)</Unit>
<Value>12565</Value>
<Timestamp>2022-09-29T14:40:22Z</Timestamp>
</DataRecord>
<DataRecord id="1">
<Function>Maximum value</Function>
<StorageNumber>5</StorageNumber>
<Tariff>0</Tariff>
<Device>0</Device>
<Unit>Volume flow (m m^3/h)</Unit>
<Value>113</Value>
<Timestamp>2022-09-29T14:40:22Z</Timestamp>
</DataRecord>
<DataRecord id="2">
<Function>Instantaneous value</Function>
<StorageNumber>0</StorageNumber>
<Tariff>2</Tariff>
<Device>1</Device>
<Unit>Energy (10 Wh)</Unit>
<Value>21837</Value>
<Timestamp>2022-09-29T14:40:22Z</Timestamp>
</DataRecord>
</MBusData>
First install libmbus, using the defaults it gets installed into
/usr/local. Debian/Ubuntu systems support that path out of the box,
but Fedora/RedHat systems may need some special incantations. The
installed library provides a libmbus.pc file, which this project use
to figure out the path to the library and include files.
Issuing
make
builds mbus-device in the current directory. Install it anywhere on
your system, and make sure to bundle the library .so file if you move
the binary to another system.
Made by Addiva Elektronik AB, Sweden. Available as Open Source under the MIT license. Please note, libmbus has a 3-clause BSD license which contains the advertising clause.