Support for ppb data type

1

I have a KNX device (Steinel True Presence) that reports some air-quality value (= VOC).

According to the KNX manual the values range from 0 - 2000 pbb and are encoded with KNX DPT 9.xxx, which is a generic DPT for floating point values.

Unfortunately I didn’t find a straight-forward way to have this data available in Home Assistant with the correct unit of measurement, etc. According to this table, there is no inherent support for ppb (parts per billion).

What is the best way to get this data into Home Assistant and have it represented correctly in the dashboard? When assigning the generic 2byte_float data type, then the value has no unit and is mis-represented in the dashboard:

Bildschirmfoto vom 2023-04-18 11-01-19

Rather than having this weird graph for data that can easily be plotted over time, I would like to have this view (e.g. for the CO2 reading, which is 9.008 i.e. ppm):

Bildschirmfoto vom 2023-04-18 11-03-04

Is is possible to have such a datatype, even though there is no dedicated DPT for it?

Or do I have to work around this with some template sensor?

2

For now I was able to “convert” the value using a template sensor:

      - name: "OG-Z1-PM1-VOC-ppb"
        unit_of_measurement: "ppb"
        device_class: volatile_organic_compounds
        state: >
          {{ states('sensor.og_z1_pm1_voc') | float }}

Obviously it would be great if none such conversion is needed.

3

I think you’d just need to add state_class: measurement and the device_class to your knx sensor entity definition to have the Ui show that graph.
Unit of measurement can be overridden in UI.

4

Unfortunately that doesn’t seem to be possible, neither via UI nor via text file.

grafik
grafik739×853 31 KB

5

Ha, alright. Then template or customize is the way to go I guess.

7

Hello Karol,
I have the True Presence but I can’t have the Presence in Home assistant.
I create an binarysensor with the address group from the Presence KO


  binary_sensor:
    - name: "Schlafzimmer"
      state_address: "1/0/1"
      device_class: motion

Can you say me if it’s right?

8

If the sensor sends 1 on presence and 0 on no presence then it is ok.
If it just always sends 1s repeatedly then you may want an event or device trigger (knx interface device).

9

Hey farmio how can I check if my sensor send 1 for presence and 0 for no presence?
I check KNX event

10

Have a look at the GroupMonitor. You’ll see what it sends there when you walk through the detector.

11

Copy
I go to the bed. I check it tomorrow.
I appreciate your help!