mqttReadTxb

Pump received messages. Payload is passed as a text buffer.

Inputs

Inputs	Data Type	Description
CnxID	STRING	Identifier of the connection in the fieldbus configuration.
PayloadTxb	DINT	Handle of a valid text buffer to be filled with the payload of the received message.

Outputs

Outputs	Data Type	Description
OK	BOOL	TRUE if a message was received.
Topic	STRING	Topic name of the received message.
QOS	DINT	Quality of service of the received message.
Retain	BOOL	TRUE if the message was retained in the broker.
Dup	BOOL	TRUE if the message was re-sent by the broker.

Remarks

The system can receive at most one message per PLC cycle. So it is not worth to loop calling this block.