Value Template, unexpected result on rounding

Configuration
1

Hi all,

after spending an hour yesterday trying to understand the root cause for an unexpected result in a value template rounding I figured to bring it up here in the hope someone is able to help.

I have data coming into HA via MQTT. The JSON in question looks like that:

    "DataRecord": [
      {
        "_id": "0",
        "Function": "Instantaneous value",
        "StorageNumber": "0",
        "Tariff": "1",
        "Device": "0",
        "Unit": "Energy (10 Wh)",
        "Value": "1444785",
        "Timestamp": "2021-11-04T07:08:20Z"
      }

I’m using the following mqtt sensor definition in HA:

  - platform: mqtt
    name: "Waermepumpe test kWh"
    state_topic: "mbusmeters/11011192434C1802"
    unit_of_measurement: "kWh"
    value_template: >-
      {%- for rec in value_json.MBusData.DataRecord %}
      {%- if ( 
              ( rec.Function == "Instantaneous value" )
         and  ( rec.StorageNumber == "0" )
         and  ( "Wh" in rec.Unit )
            ) -%}
      {{ rec.Value | float(0) / 1000 | round(2) }}
      {%- endif %}
      {%- endfor %}

What I’m expecting from the input number “1444785” is the output “1444.785” and trying it out in the template editor gives exactly that result.
The sensor value though ends up with “1444.7850.0” and I can’t get my head around on why and where the 0.0 is getting added to the end. I tried multiple different versions of the sensor defintion, bracketing parts of the formula without luck - it always leads to the same result.

Leaving away the round btw gives me “1444785” as expected.

2

Wild guess:
You have a second record validated by the “If” whose result is “0.0” (the 1444.785 part doesn’t make sense unless you have a typo or a “/1000” somewhere)

1 Like
4

You were right: It matched a second record given there are ones for different tariffs.
The fix was simple (add the Tariff as a condition) and in case someone uses a similar meter:

    value_template: >-
      {%- for rec in value_json.MBusData.DataRecord %}
      {%- if ( 
              ( rec.Function == "Instantaneous value" )
         and  ( rec.StorageNumber == "0" )
         and  ( rec.Tariff == "1" )
         and  ( "Wh" in rec.Unit )
            ) -%}
      {{ rec.Value | float(0) / 100 | round(2) }}
      {%- endif %}
      {%- endfor %}

Thx koying!