MQTT Client
Set up connection to external MQTT broker
The MQTT client can be used to establish a connection to an external MQTT server (broker) or one that is available in the site network.
If data point values are to be exchanged across sites in relation to the HOOC solution, an MQTT client of site A can use Secure Proxy Permalink to establish a connection to the Remote Control service of site B and thus exchange data point values via the API provided.
| Property | Description |
|---|---|
| Protocol type | Select MQTT Client |
| Name | Enter the name of the device |
| Description | Enter the description of the device |
| IP address / host | IP address / host of the MQTT broker |
| Port | Default port 1883 |
| TLS connection | The connection to the MQTT broker is encrypted |
| MQTT Client ID | Specifiy the Client ID of the device |
| Username | Authentication information (optional) |
| Password | Authentication information (optional) |
| Topic prefix ‘READ’ | Choose this option in order to read data (optional) |
| Topic prefix ‘WRITE’ | Choose this option in order to write data (optional) |
| Connection monitoring | If this field is checked, all data points will not be marked as invalid in case of an interruption of the connection (last known value). For the connection monitoring to work, it is mandatory to specify the MQTT Client ID. |
| Validity period | Please note that if no value update is received during the predefined Intervall, the corresponding data point will be marked as invalid (Last known value). |
Actions
The setup of a MQTT device allows a number of possible actions.
| Action | Description |
|---|---|
| Edit interface settings | |
| Export data points (if data points available) | |
| Import Datenpunkte (if no data points available) | |
| Remove interface (if no data points available) |
Data points
The live values of the acquired data points are automatically displayed. By clicking on the icon, you can stop the data monitor.
By clicking on the icon, a new data point will be created for the corresponding interface.
| Property | Description |
|---|---|
| Interface / Device | Select the device / interface |
| Topic ‘read’ (optional) | Optionally, enter the enlarged topic for data reading (the enlarged topic is the addition to the prefix already entered under Change settings / topic “read”) |
| Decoder | Select and enter settings for the data decoder |
| Topic ‘schreiben’ (optional) | Optionally, enter the enlarged topic for data writing (the enlarged topic is the addition to the prefix already entered under Change settings / topic “write”) |
| Encoder | Select and enter the settings for the data encoder |
| Data point | Enter the name of the data point |
| Description | Enter a description of the data point |
| Data type | Select a data type |
| Conversion | If required, values can be linearized, e.g. temperature in tenths to °C with one decimal place |
| Unit | Units in LaTeX format: e.g. ^\circ C for °C |
Custom encoder and custom decoder
In order to encode or decode data, select accordingly ‘encoder’ or ‘decoder’. The templates of the functions (Javascript) are displayed in the editor. More information about the parameters and return values can be found in the table below:
| Property | Decoder | Encoder | Description |
|---|---|---|---|
Parameter raw |
x | Byte array of raw data | |
Parameter value |
x | Data point value in the corresponding format (number, bool, string) | |
Parameter dataType |
x | x | Used data type of the data point (one of the following strings: “Int8”, “Int16”, “Int32”, “UInt8”, “UInt16”, “UInt32”, “Float32”, “Float64”, “Bool”, “String”) |
| Return value Decoder | x | Return value based on used data type (number, bool, string) | |
| Return value Encoder | x | Byte array |
In order to analyze data and implement custom encoders and custom decoders, it is recommended to activate the MQTT debug mode. (use near to Interfaces/Devices).
Actions
The setup of a data point allows a number of actions.
| Action | Description |
|---|---|
| Edit data point settings | |
| Edit Smart UI settings | |
| Show data point trend | |
| Write value of the data point (if writable) | |
| Duplicate data point | |
| Remove data point |