Protocols¶

MQTT¶

Characteristics¶

Information Model Requirements

The first Node after the root node must be of type Event .
The following Node Types can be used under the Event Node:
- Variables with a Simple Data Type represents the key-value pairs.
- Variables with a Custom Data Type represent objects that can contain key-value pairs.
- With Lists you can aggregate multiple variables.
In case of publishing a topic, the Information Model determines the structure of the payload.
In case of subscribing to a topic make sure that the Information Model structure matches the payload.

How to configure the MQTT Channel¶

Select the MQTT (JSON) as Channel Type.
Click the Configure button.

Select the root model node
Enter host and port of the MQTT Broker used.
Specify a path to a folder on your local machine. The temp directory inside the SMARTUNIFIER Manager can be also used.
Enter user name and password. If there are no credentials needed (e.g., test.mosquitto.org) make sure the fields remain empty.

Select the event node in the tree on the left.
Enable either producer or consumer depending on the use case and enter a topic name.
Click the Apply button.

Certificates

Encrypted connection using TLS security is supported. Follow the steps below to encrypt the connection.

Enable the Tls checkbox
Enable the Tls Configuration checkbox

Enter the path to the CA (certificate authority) certificate of the CA that has signed the server certificate

Note

Make sure the CA certificate is valid.

Enable the Client checkbox

Enter the path to the client certificate. The client certificate identifies the client just like the server certificate identifies the server.
Enter the path to the private client key.
If applicable enter the password
Select the protocol from the Drop-Down.

Disconnected Buffer

In case the connection is lost, messages can be buffered offline when the Disconnected Buffer is enabled. Follow the steps below to enable the DisconnectedBuffer.

Enable the DisconnectedBuffer checkbox.
Set the Buffer Size - defines the amount of messages being hold e.g., 5000.
(Optional) Enable PersistBuffer.
(Optional) Enable DeleteOldestMessage.

Description of configuration properties:

Property	Description	Example
host	URL of the MQTT Broker.	`test.mosquitto.org`
port	Port of the MQTT Broker.	`1883`
reconnectInterval	Time interval to reconnect to the MQTT Broker after loss of connection in seconds	`5`
connectionTimeout	Time interval the connection times out in seconds	`60`
keepAliveInterval	Time the session persists in seconds	`60`
persistenceFolder	Path to a folder for the persistence store of the MQTT	`temp`
clientId	Identifies an MQTT client which connects to an MQTT Broker	`MyClientID`
username	Client username	`Username`
password	Client password	`Password`
hostnameVerification	Hostname Verification	`true`, `false`
tls	Encryption	`true`, `false`
producers	Data producer	`true`, `false`
consumer	Data consumer	`true`, `false`
protocol	TLS protocol version	`TLSv1.1`, `TLSv1.2`
disconnectedBuffer	Offline buffering of data	`true`, `false`
bufferSize	Amount of message allowed in the buffer	`5000`
persistBuffer	Buffer persistence	`true`, `false`
deleteOldestMessage	Delete oldest message in buffer	`true`, `false`

OPC-UA¶

Characteristics¶

OPC (Open Platform Communications) enables access to machines, devices and other systems in a standardized way. To learn more about the standard visit the OPC-UA website.

Information Model Requirements

The following Node Types can be used to model data structures:
- Variables with a Simple Data Type.
- Variables with a Custom Data Type.

OPC-UA Client¶

Select OPC-UA Client as Channel Type.
Click the Configure button.

Make sure the root model node is selected to configure the OPC-UA Client
Enter an applicationName
Configure the serverTcpConfiguration

Enter an ipAdress
Enter the port
Define an endpoint
Set a requestTimeOut

Configure the defaultSubscriptionAttribute

Define a publishingInterval

Configure monitoringParameters

Set a samplingInterval
Enter a queueSize
Enable discardOldest depending on the use case

Assign OPC-UA data block variables to corresponding variables in the Information Model by selecting the variable in the tree
Assign data block

Enable the variables checkbox
Enter the nodeId

REST¶

REST Server¶

Select the root model node in the tree on the left.
Enter a path prefix.
Configure the REST Server endpoint.

Enter the IP.
Enter the port.
Enter the Content-Type.

Check the webapp checkbox and provide the WAR-file if you want to host an application.
Click the Apply button and save the Channel by clicking the Save button on the upper right corner.

Description of configuration properties:

Property	Description	Example
pathPrefix	Prefix for the URL	`e.g., demo`
Port	Port of the REST server	`e.g., 9002, 9000, ...`
IP	IP address of the REST server	`http://localhost`
DefaultContentType	Is used to indicate the media type of the resource	`application/json`, `application/xml`, `text/html`, `text/csv`
webapp	Possibility to host an application	`true`, `false`

REST Client¶

Select the root model node in the tree on the left.
Configuration of the REST Client

Enter the IP.
Enter the Default-Content type.
Enter a timeout.

Click on the variable in the tree which needs a configuration.
Check the checkbox.
Variable configuration.

Enter the URL.
Select the HTTP method.

Click on the Add Header button to add headers.
Check the headers checkbox.
Configure Key-Value pair of the header.

Enter a name.
Enter a value.

Click the Apply button and save the Channel by clicking the Save button on the upper right corner.

Description of configuration properties:

Property	Description	Example
URL	URL of the REST Server.	`localhost:8090`
RouteModelPath	Path of a node in the Information Model. A node can be a command, an event or a variable	`/Model/RestMetrics/Event/partQualityEvent`
RouteUrl	URL of the exposed node .	`localhost:8090`
HttpMethod	HTTP method for the action performed by the Client.	`GET`, `POST`, `PUT`
HeaderName and Header Value	To provide server and client with additional information	`Retry-After: 12`
ContentType	Is used to indicate the media type of the resource.	`application/json`
WaitTimeoutDuration	Timeout in seconds until request is failing	`10`