How to assign more than one MQTT Message to a Channel

Setup, Configuration and Use Items & Sitemaps
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1

I am using a Tasmota device with a lot of inputs which i want to use in openHAB.This works in general with openHAB2.5 and MQTT 2.5.1.

The Tasmota device sends a MQTT-Message
stat/RESULT = {“Time”:“2020-06-29T12:55:39”,“MCP230XX_INT”:{“D0”:0,“MS”:1305604}} or
stat/RESULT = {“Time”:“2020-06-29T12:56:07”,“MCP230XX_INT”:{“D0”:1,“MS”:28480}}

when the status of the input changes.

Every 5 minutes It also sends a
tele/SENSOR = {“Time”:“2020-06-29T12:54:02”,“MCP230XX”:{“D0”:1,“D1”:1,“D2”:1,“D3”:1,“D4”:1,“D5”:1,“D6”:1,“D7”:1,“D8”:0,“D9”:0,“D10”:0,“D11”:0,“D12”:0,“D13”:0,“D14”:0,“D15”:0}}
message which includes the stati of all inputs.

So i defined in a .things file:

Thing mqtt:topic:Homeio "Home IO" (mqtt:broker:myMqttBroker)  {
    Channels:
    Type switch : In0 "Home IO In 0"      [ stateTopic="tele/SENSOR", transformationPattern="JSONPATH:$.MCP230XX.D0", on="0", off="1" ]
   
    Type switch : In0 "Home IO In 0"      [ stateTopic="stat/RESULT", transformationPattern="JSONPATH:$.MCP230XX_INT.D0", on="0", off="1" ]

}

I want to use the two different message-types to set the status of the item, because if an stat/RESULT message gets lost the staus should be set at least every 5 Minutes from the tele/SENSOR message.

and in my .items file:

Switch   OG1_Homeio_in0	     "Test Taster 0"    ( G_HOMEIO ) { channel="mqtt:topic:Homeio:In0" }

But it does not work as expected. Only the stat/RESULT message sets the item. I don’t know the right method to set the item from two different MQTT-Messages.

Has anyone an idea?

Michi

2

You must give your channels different, unique names. In0A and In0B perhaps. Then you can link two channels to one Item

3

But how to link two channels to one item?

4 
Switch   OG1_Homeio_in0	     "Test Taster 0"    ( G_HOMEIO ) { channel="mqtt:topic:Homeio:In0", channel="mqtt:topic:Homeio:In1" }

Separate the channels with a comma. Note that I just made up that second channel - it depends on what you decide to name it!

5

really easy solution (if you know how to…). It works perfectly now.

Thanks a lot

6

It was a hidden feature to me too until not long ago.

It’s way down the page in the docs…

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