MQTTPUB
This block publish a message on a given MQTT topic.
Library
Communicate
Description
MQTTPUB allows to publish a message to any MQTT-broker.
Example
To connect to Altair IoT Studio, the hostname is set to 'mqtt.swx.altairone.com'. The topic defines the space, thing, and properties under which Twin Activate data is stored.
It is required to use JavaScript Object Notation (JSON) format to send data to IoT Studio. The message looks like
{
"obj1":{
"time": "%%1",
"amplitude":"%%2"
}
}
The tutorial Connect to an MQTT Broker using Twin Activate (Tutorials - Integration and Collaboration) describes all necessary actions in IoT Studio and Twin Activate step by step.
Parameters
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
hostname | Hostname | Defines the broker's IP address | String | |
port | Port | Defines the port number to use | Scalar | |
username | Username | Defines the username for authentication. | String | |
password | Password | Defines the username for authentication. | Vector | |
topic | Topic | Defines the topic where the message will be published. | String | |
connection | Connection | Defines the MQTT clean session flag. | Structure | |
connection/clean | Clean session | Number | 0 | |
connection/persistent | Persistent session | Number | 0 | |
retain | Retain message | If set, the message will be retained. | Number | 0 |
qos | Quality of Sevice | Defines the Quality of Service to be used for the connection. | Structure | |
qos/qos0 | 0 | This level guarantees a best-effort delivery. There is no guarantee of delivery. The recipient does not acknowledge receipt of the message and the message is not stored and re-transmitted by the sender. | Number | 0 |
qos/qos1 | 1 | This level guarantees that a message is delivered at least one time to the receiver. The sender stores the message until it gets a PUBACK packet from the receiver that acknowledges receipt of the message. It is possible for a message to be sent or delivered multiple times. | Number | 0 |
qos/qos2 | 2 | This level guarantees that each message is received only once by the intended recipients. It is the safest and slowest quality of service level. | Number | 0 |
keepalive | Keep alive | Defines the number of seconds after which the broker should send a PING message to the client if no other messages have been exchanged in that time. | Scalar |
| Name | Label | Description | Data Type | Valid Values |
|---|---|---|---|---|
nin | Number of Inputs | Defines the number of inputs | Number | |
message | Message | Defines the message to be published. This message can be of any format (text, JSON, ...). User can use %%1, %%2, ..., %%n to identify the inputs. | String | |
separator | Array separator | Defines the separator used for arrays elements. | String | |
onFailure | Do on failure | Defines the behavior on failure. | Structure | |
onFailure/error | Error | Number | 0 | |
onFailure/warning | Warning | Number | 0 | |
verbose | Verbose | If set, some information are written in the OML command windows. This flag help to debug. | Number | 0 |
Ports
| Name | Type | Description | IO Type | Number |
|---|---|---|---|---|
Port 1 | explicit | input | nin | |
Port 2 | activation | input | 1 |