Capture energy sources via WiFi with TASMOTA

Step by step.

Before one can manage one's energy sources and consumers, it is first necessary to record as many consumers and energy sources as possible in the system with measuring points. Missing measuring points that cannot be integrated directly into KNX must be integrated via alternative BUS systems. One of these options is the integration of WiFi-capable ESP WLAN radio modules with the TASMOTA firmware. The energy values can be queried via HTTP request in the local network and, depending on the radio module, switching operations are also possible.

The integration of a TASMOTA meter in KNX takes place via the EIBPORTwhich has all the necessary interfaces and integration modules for this and has integrated diverse visualisation tools for all possible end devices. The following example describes the integration of a TASMOTA top-hat rail electricity meter into the web visualisation with CONTROL. L.

  • After mounting the electricity meter, you should energise it and access its WLAN.
  • For the first login, use the default IP address
  • In the configuration menu, go to "Configure WiFi" and enter the settings for your own network.
  • After you have saved the settings, you can access the unit on your network.
  • The measured values are already displayed in the "Main Menu".
  • If necessary, calibrate the meter with a resistive load.

Integration of the TASMOTA measured values by means of a logic group in the EIBPORT

To integrate the TASMOTA meter into the KNX system, it must be assigned a fixed IP address. By default, the meter is set to DHCP, the change to a static IP address is done by programming via the "Console".

The measured values are integrated into the KNX system via a logic group in the EIBPORT. For this purpose, the LOGIC EDITOR is called up in the EIBPORT and the logic group is imported or created. The logic group for an http request and the transmission of the measured values into the KNX requires only a few logic elements, which can be selected under "+ Add".

  • 2 Input values: Query the values and enable the logic group
  • Cyclical transmitter, e.g. every hour
  • Configuring the send command via HTTP request
  • Text processor for evaluating the desired values
  • 7 Output values: Selection of the values to be transmitted to the KNX system.

Transfer measured values from TASMOTA meters to the KNX bus
To transfer the measured values from TASMOTA meters to the KNX bus, various steps are carried out:

  1. Updating the measured values: The measured values are updated by a query. Care is taken to keep the KNX bus load low.
  2. Enabling the logic group: Enabling activates or deactivates the logic group.
  3. HTTP request: The "GET" request has the format: http:///cm?cmnd=Status0. The response of the TASMOTA counter is evaluated.
  4. Text processor: The desired values are filtered from the response by the text processor.
  5. Output values: The desired values are written to the KNX bus as data point type (DPT) 14.*.

Through these steps, the measured values are available in the required data format in order to be able to display them in a visualisation. The display takes place in the example web visualisation CONTROL L. The visualisation elements "Switch", "Button", "Dynamic text" or "Graphic element" can be used here. The measured values are output via the visualisation element "Value display" with the corresponding DPT 14.* or EIS 9 (4 byte FP).

As this value display can be created easily and quickly, it lends itself as a copy template for other counters.

The measured values can now be used flexibly in the KNX bus. The TASMOTA meter also has a switching function with which connected loads can be switched off, e.g. in standby mode. This function can also be integrated into the KNX by downloading another logic group.