MQTT and the use of string constants and concatenation in the State_topic

Configuration
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1

Hi,

Use a quick one.
Is it possible to use sring constants and concatenation within the State_topic of a MQTT template.?

The reason that I ask is that for my MQTT template the core part of the State_topic is the same for each entity.

I have tried using ‘input_text’ for this and I get the correct text when using the ‘Developer tools template’, but when I try and use the same structuture within the MQTT template I get a returned value of ‘unknown’.

In my configuation file I have

input_text:
  ihd_state:
    name: IHD State
    initial: "glowaintree/84CCA8544CC4/"

In the developer tool template I use:

{{states('input_text.ihd_state')}}SENSOR/electricitymeter

giving me the correct value of:

glowaintree/84CCA8544CC4/SENSOR/electricitymeter

when I encorporate this in the MQTT template as:

sensor:
  - name: "Smart Meter test"
    unique_id: "smart_meter_test"
    state_topic: "{{states('input_text.ihd_state')}}/SENSOR/electricitymeter"
    device_class: "energy"
    unit_of_measurement: "kWh"
    state_class: "total_increasing"
    value_template: "{{ value_json['electricitymeter']['energy']['export']['cumulative'] }}"
    icon: "mdi:flash"

The unique ID returns unknown.

Thanks for any help tthat you can give me.

Graham.

2

I don’t think you can define a MQTT entity like that.

3

state_topic takes a string, not a template

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