Documentation

Data

The value that should be written to the topic in the remote broker. The port inherits the data type and the dimensions from the connected sink block. The data type and dimensions do not both need to match the data type and dimensions of the record in the remote slave device, but the overall number of bytes must be equal to or less than the size of the record.

Data type: Fundamental data types from Boolean to double are supported as well as dimensions from scalar values to vectors

Enable

If enabled by the Extended Interface parameter, the block sends out publish messages as long as the input port is TRUE.

If disabled, the block sends out publish messages on each sample hit, according to the Sample Time parameter, and without checking data changes.

Best practice is to set the block's sample time to a higher rate (like the model's base sample time) and trigger the Enable input port at a lower rate. You could also connect this port with the output port of a Detect Change block and connect the input port with your data to be sent. This ensures low network traffic as the block will send publish messages only on data changes.

Data type: Boolean

Length

The actual size of the data that should be written to the topic, specified in number of bytes.

If enabled by the Extended Interface parameter, the port limits the size of the data to be written to the topic. The publish message will contain a subset of the signal connected with the Data input port.

If disabled, the entire signal connected with the Data input port will be written to the topic. This is also the case, if you ground the Length input port or do not connect it at all.

Data type: uint32

This block does not have any output ports.

Station ID

Apply the Station ID of the corresponding Setup block. Must range between 0 and 65535.

Connection ID

Apply the Connection ID of the corresponding Connection block. Must range between 0 and 65535.

Topic

The topic whose data you want to publish. Topic is a character array.

Use the / character to build paths and address specific topic levels. Examples:

Publish topic 'attribute7' of parent topic 'group0/port3':

'group0/port3/attribute7'

Publish topic 'port3' of parent topic 'group0':

'group0/port3'

Quality of Service

The Quality of Service is a flag in the publish message and tells the broker on how to quarantee the delivery of messages.

• 0 - at most once: The broker does not confirm the receipt of a data message and the message is not retransmitted by the Publisher. This level allows the broker to immediately procees the message received and allows the Publisher not to have to preserve messages for retransmission.

• 1 - at least once: The broker confirms the receipt of a data message by sending an acknowledge to the Publisher. If the Publisher does not receive a confirmation in a specific amount of time, the same data message is transmitted again.

• 2 - exactly once: The broker confirms the receipt of a data message twice using a 4-way handshake. If the Publisher does not receive the confirmation in a specific amount of time, the same data message is transmitted again. This level increases the overall time for processing data messages but ensures that the same data is not processed multiple times.

Retain

The Retain flag in the publish message tells the remote broker to save the last data received. This allows newly subscribed clients to receive an immediate topic update.

Extended Interface

If selected, the block shows the Enable and the Length input ports. Otherwise, the ports are hidden.

Sample Time

Defines the base sample time at which this driver block gets its sample hit. This parameter can also be set to -1 for inherited sample time. The units are in seconds.