KNX Item gets value from different KNX Item

Ok I got the following issue with my OpenHAB configuration (text based) in combination with my KNX items.

I got a status value getting the knx bus current drawn by the knx power supply. In addition I got a binary actuator getting pulses from the heat pump’s energy meter.

This are the two things:

Bridge knx:ip:bridge "MDT IP Router" [  
] {

    // power supply
    Thing device bs1_1_0_1 "BS1 - MDT Busspannung Haus Innen" @ "KNX Verteilung" [ 
    ] {
        Type number : knxBusHausStromMesswert  "KNX Bus Haus - Strommesswert" [ ga="7.012:<5/0/0" ]

    // binary actuator
    Thing device be1_1_0_27 "BE1 - MDT Binäraktor" @ "KNX Verteilung" [ 
    ] {
        Type number : chE  "Wärmepumpe - Zählerimpulse" [ ga="13.001:<5/1/0" ]

and here are the two items:

//- knx bus haus
Number knxBusHausStromMesswert "KNX Bus Haus - Strommesswert [%.0f mA]" <energy> (knxBus) { channel="knx:device:bridge:bs1_1_0_1:knxBusHausStromMesswert" }

//- waermepumpe
Number waermepumpeZaehlerImpulse "Wärmepumpe - Stromverbrauch [%d Wh]" <energy> { channel="knx:device:bridge:be1_1_0_27:chE" [profile="offset", offset="901230"] }

So most of the time everything works as expected and the two items get its correct values from the system. But I was wondering why the value of the counted pulses of the energy meter are sometimes completely off.

I went through the logs and discovered the following.

ETS group address monitor looks fine. The energy pulses are correctly sent to the bus.

In the openhab log you can see that suddenly the value of the energy pulses goes down to 171. If you step one line below you can see that at the same time the knx power supply’s current value gets set to 171 (which is correct for the power supply).

I searched through the logs and found more of it like:

2020-02-23 05:57:34.302 [vent.ItemStateChangedEvent] - waermepumpeZaehlerImpulse changed from 913180.0 to 152.0
2020-02-23 05:57:34.304 [vent.ItemStateChangedEvent] - knxBusHausStromMesswert changed from 133.0 to 152.0
2020-02-23 05:57:35.279 [vent.ItemStateChangedEvent] - waermepumpeZaehlerImpulse changed from 152.0 to 134.0
2020-02-23 05:57:35.283 [vent.ItemStateChangedEvent] - knxBusHausStromMesswert changed from 152.0 to 134.0

WTF is going on there? :slight_smile: I would love to see your help in this problem. I can’t discover the error in my configuration. It looks like a timing issue somehow since it only happens sometimes and most of the time only when both values get changed at nearly the same time.

What can I do to get a better picture of what the knx binding is receiving?

Here is my overall setup:

  • Platform information:
    • Hardware: Raspberry Pi 4 with 4GB of memory and 64 GB SD card
    • OS: OpenHabian latest version it ZRam enabled
    • Java Runtime Environment: OpenHabians Java
    • openHAB version: 2.5.2