MQTT Client

note this driver is available for litmus edge version 3 5 2 and later you can set up an mqtt client through devicehub note you can't connect the mqtt client to the devicehub docid\ zc7ycu8fronkfgnj2fcbn if they are using the same litmus edge instance this includes connecting through the flows manager or through an integration connector if they are using different litmus edge instances, they can connect step 1 add mqtt client to devicehub to add the mqtt client to device hub in litmus edge, navigate to devicehub click the connect a device box the connect device dialog box appears for driver type , select mqtt then, for driver name , select mqtt client enter a name for the client optionally, add a description for broker address , enter the broker ip address or host name for port , enter the port of the broker configure the client with the following options client authentication select one of the following client authentication methods anonymous certificate (only for ssl mode) username/password username/password & certificate update the default username and password values as needed security mode if you enable security mode, upload or paste the certificate in the certificate authority field will enabled (last will and testament) if you enable a last will and testament, (lwt) configure the following will topic enter the topic for the last will and testament will payload enter the payload in string format will qos select one of the following message delivery options 0 at most once (fire and forget) 1 at least once (acknowledged delivery) 2 exactly once (assured delivery) will retained select enable or disable advanced if you show these options, configure the following as needed client id enter the mqtt client id the default client id is the devicehub device name persistent session select enable or disable certificate verification select enable or disable protocol version select the mqtt protocol version v3 (3 1), v4 (3 1 1), v5 (5 0) keep alive period configure the keep alive period in seconds write timeout configure the write timeout in seconds connect timeout configure the connect timeout in seconds additional options see the docid 3eyafppweuvmblcey17sq section to learn more about additional options when done configuring the device, click add device step 2 add tags when you docid 8se7z3pmrfwl1nmzcwalx to the connected device refer to the following tag parameters tag parameters name enter the case sensitive topic name in the server without any wildcard symbols the name must be unique for the driver value type select string tag name enter a name for the tag description (optional) enter a description for the tag qos select a quality of service 0 at most once (fire and forget) 1 at least once (acknowledged delivery) 2 exactly once (assured delivery) retain select a message policy don't retain retain last publish tag formula enter a formula for the tag to process the generated data two variables are permitted value (current tag value) and timestamp (current tag unix time in milliseconds) the following math functions are available sin cos sqrt tan power power( x ) performs the operation 10^x log log( x ) is the natural logarithm (the logarithm is in base e ) exp exp( x ) performs the operation e^x only publish on change of value select the checkbox to customize nats messages to be published only when the value parameter changes from a previous value to a new one change of value only applies to boolean, numeric (such as int or float), and simple string data types it does not apply to complex types, such as json or array poll once topics will not be affected by change of value settings these topics will still only see a single message meta data metadata summarizes basic information about data this feature allows you to define key value pair data for the device output payload later on it can then be used to find, use, and reuse particular instances of data note if you use special characters in meta data key names, the special characters are replaced with underscore characters in the payload this can cause two key names to be combined into one for example, configuring the key names a b and a&\&b will cause only one key name to be created (a b) step 3 connect to mqtt server once the client is connected in litmus edge with tags, you can connect it to an mqtt server note you can't connect the mqtt client to the devicehub docid\ zc7ycu8fronkfgnj2fcbn if they are using the same litmus edge instance if they are using different litmus edge instances, they can connect