MQTTSubscribe (FB)¶

FUNCTION_BLOCK MQTTSubscribe EXTENDS CBML.LCon IMPLEMENTS ISubscriber

Function block to subscribe (receive) messages from a MQTT broker

InOut:

Scope	Name	Type	Initial	Comment	Inherited from
Input	`xEnable`	`BOOL`		`TRUE`: Activates the defined operation `FALSE`: Aborts/resets the defined operation	LCon
Output	`xDone`	`BOOL`		`TRUE`: Ready condition reached	LCon
	`xBusy`	`BOOL`		`TRUE`: Operation is running	LCon
	`xError`	`BOOL`		`TRUE`: Error condition reached	LCon
Input	`eSubscribeQoS`	MQTT_QOS		QoS-Level for Subscribe
	`pbPayload`	POINTER TO BYTE		Pointer to memory for incoming payload
	`udiMaxPayloadSize`	`UDINT`		Maximum Size of incoming payload
	`eFilterMode`	FILTER_MODE	FILTER_MODE.FILTER_ON	Filter mode for incoming telegrams. Default: FILTER_MODE.FILTER_ON
	`mQTTSubscribeProperties`	REFERENCE TO MQTTSubscribeProperties		Subscribe proerties (MQTT V5 only)
	`udiTimeout`	`UDINT`	1000000	Time in µs in which an subcription acknowledgement (SUBACK) must be received.
Inout	`mqttClient`	MQTTClient		Function block MQTTClient
Inout	`wsTopicFilter`	`WSTRING(1024)`		Topic Filter
Output	`eMQTTError`	MQTT_ERROR		MQTT Error Type
	`xReceived`	`BOOL`		FALSE as long as there is no message, TRUE if a message got received, in new cyclus then again FALSE
	`udiPayloadSize`	`UDINT`		Size of the received message
	`xSubscribeActive`	`BOOL`	FALSE	FALSE: When there is no active subscription, TRUE: Subscriber is listening
	`wsLastTopic`	`WSTRING(1024)`		The real topic value from the publish packet that is corresponding to this topic filter
	`mQTTPublishProperties`	MQTTPublishProperties		Last received publish properties

Properties:

FilterMode

SubscribeActive

Structure: