wmbusmeters

The program receives and decodes C1 telegrams (using the wireless mbus protocol) to acquire utility meter readings.

OS/Compiler	Status
Linux G++

wmbusmeters version: 0.4
Usage: wmbusmeters {options} (auto | /dev/ttyUSBx)] { [meter_name] [meter_type] [meter_id] [meter_key] }*

Add more meter quadruplets to listen to more meters.
Add --verbose for detailed debug information.
    --robot or --robot=json for json output.
    --robot=fields for semicolon separated fields.
    --separator=X change field separator to X.
    --meterfiles=dir to create status files below dir,
          named dir/meter_name, containing the latest reading.
    --meterfiles defaults dir to /tmp.
    --oneshot wait for an update from each meter, then quit.

Specifying auto as the device will automatically look for usb
wmbus dongles on /dev/im871a and /dev/amb8465.

Two meter types are supported: multical21 and multical302 (multical302 is still work in progress).

Currently the meters are hardcoded for the European default setting that specifies what extra data is sent in the telegrams. If someone has a non-default meter that sends other extra data, then this will show up as a warning when a long telegram is received (but not in the short telegrams, where wrong values might be printed instead!). If this happens to someone, then we need to implement a way to pass the meter configuration as a parameter.

No meter quadruplets means listen for telegram traffic and print any id heard.

Usage examples

./build/wmbusmeters /dev/ttyUSB0 MyTapWater multical21 12345678 00112233445566778899AABBCCDDEEFF

wmbusmeters will detect which kind of dongle is connected to /dev/ttyUSB0. It can be either an IMST 871a dongle or an Amber Wireless AMB8465. If you have setup the udev rules below, then you can use auto instead of /dev/ttyUSB0.

Example output:

MyTapWater 12345678 6.388 m3 6.377 m3 DRY(dry 22-31 days) 2018-03-05 12:02.50

Example robot json output:

./build/wmbusmeters --robot=json auto MyTapWater multical21 12345678 00112233445566778899AABBCCDDEEFF MyHeater multical302 22222222 00112233445566778899AABBCCDDEEFF

{media:"cold water",meter:"multical21","name":"MyTapWater","id":"12345678","total_m3":6.388,"target_m3":6.377,"current_status":"DRY","time_dry":"22-31 days","time_reversed":"","time_leaking":"","time_bursting":"","timestamp":"2018-02-08T09:07:22Z"}

{media:"heat",meter:"multical302","name":"MyHeater","id":"22222222","total_kwh":0.000,"total_volume_m3":0.000,"current_kw":"0.000","timestamp":"2018-02-08T09:07:22Z"}

Example robot fields output:

./build/wmbusmeters --robot=fields auto GreenhouseWater multical21 33333333 ""

GreenhouseTapWater;33333333;9999.099;77.712;;2018-03-05 12:10.24

You can use --debug to get both verbose output and the actual data bytes sent back and forth with the wmbus usb dongle.

If the meter does not use encryption of its meter data, then enter an empty key on the command line. (you must enter "")

./build/wmbusmeters --robot --meterfiles auto MyTapWater multical21 12345678 ""

You can run wmbusmeters with --logtelegrams to get log output that can be placed in a simulation.txt file. You can then run wmbusmeter and instead of auto (or an usb device) provide the simulationt.xt file as argument. See test.sh for more info.

Builds and runs on GNU/Linux:

make && make test

Binary generated: ./build/wmbusmeters

make HOST=arm

Binary generated: ./build_arm/wmbusmeters

make DEBUG=true

Binary generated: ./build_debug/wmbusmeters

make DEBUG=true HOST=arm

Binary generated: ./build_arm_debug/wmbusmeters

System configuration

Add yourself to the dialout group to get access to the newly plugged in im871A USB stick. Or even better, add this udev rule:

Create the file: /etc/udev/rules.d/99-usb-serial.rules with the content

SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", SYMLINK+="im871a",MODE="0660", GROUP="yourowngroup"
SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", SYMLINK+="amb8465",MODE="0660", GROUP="yourowngroup"

When you insert the wmbus USB dongle, a properly named symlink will be created: either /dev/im871a or /dev/amb8465. These symlinks are necessary if you want to pass "auto" to wmbusmeters instead of the exact serial port /dev/ttyUSBx.

Limitations

Two usb wmbus receivers are supported: IMST im871A and Amber Wireless AMB8465.

Two supported meters: Multical21 (water meter) and Multical302 (heat meter?, work in progress).

The source code is modular and it should be relatively straightforward to add more receivers and meters.

Good documents on the wireless mbus protocol:

http://www.m-bus.com/files/w4b21021.pdf

https://www.infineon.com/dgdl/TDA5340_AN_WMBus_v1.0.pdf

http://fastforward.ag/downloads/docu/FAST_EnergyCam-Protocol-wirelessMBUS.pdf

http://www.multical.hu/WiredMBus-water.pdf

http://uu.diva-portal.org/smash/get/diva2:847898/FULLTEXT02.pdf

The AES source code is copied from:

https://github.com/kokke/tiny-AES128-C

The following other github projects were of great help:

https://github.com/ffcrg/ecpiww

https://github.com/tobiasrask/wmbus-client

https://github.com/CBrunsch/scambus/

TODO: CRC checks are still missing. If the wrong AES key is supplied you probably get zero readings and sometimes warnings about wrong type of frames.