MQTTCLIENT

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This driver acts as an MQTT client (publisher/subscriber) for Hsyco, it fully supports MQTT version 3.1.1. This driver uses Java methods from the library Eclipse Paho, version 1.2.2.

HSYCO Configuration

Add the MQTTCLIENT I/O Server in the I/O Servers section of the Settings and set its parameters:

Communication

  • IP Address: host name or IP address of the MQTT broker
  • IP Port: TCP/IP port of the MQTT broker

Authentication

  • User: username for authentication with MQTT broker
  • Password: password for authentication with MQTT broker

Options

ID Default Values Description
startupevents false true generate IO events also during the driver’s start-up phase
false start generating events only after HSYCO is aligned with the current status of the system
cleansession false true cleans eventually existing previous session held by the MQTT broker. This will remove any previous subscription and unacknowledged messages
false restores eventually existing previous session held by the MQTT broker. This will restore all existing subscriptions and resend any unacknowledged message
messageretain false true with this option true the MQTT broker will save publish messages for future subscribers
false with this option false the MQTT broker will not save publish messages for future subscribers
keepalive 60 n >= 0 this value, measured in seconds, defines the maximum time interval between messages sent or received. It enables this driver to detect if the MQTT broker is no longer available. In the absence of a data-related message during this time period, the client sends a very small "ping" message, which the server will acknowledge. A value of 0 disables keepalive processing in the client.
connecttimeout 30 n >= 0 this value, measured in seconds, defines the maximum time interval this driver will wait for the network connection to the MQTT broker to be established. A value of 0 disables timeout processing meaning the driver will wait until the network connection is made successfully or fails.
messageqos 0 0 every publish message is sent at most one time, so it doesn't receive acknowledge message from the MQTT broker
1 every publish message is sent at least one time, so it waits acknowledge message from the MQTT broker
2 every publish message is sent exactly one time, so there will be a series of acknowledge messages between the MQTT client and broker

Subscriptions file

Under the hsyco root directory there could be a file named "mqttsubscriptions-<IOServerId>.ini" (e.g "mqttsubscriptions-myclientid.ini") which can contain a series of line, each line represents a topic to subscribe and the topic's quality-of-service (qos). On each line topic and relative qos are separated by a white space:

E.g.

/mqtt/test 2

home/bathroom 1

/outdoor 0


Datapoints

ID Value R/W Description
connection online R the client is connected to the MQTT broker
offline R initialization of the driver failed or loop cycle failed
received.<topicName> <message> R the client received a message on topicName
publish.<topicName> <message> R/W the client published a message on topicName
subscribe.<topicName> 0 R/W the client subscribes to topicName with qos=0
1 R/W the client subscribes to topicName with qos=1
2 R/W the client subscribes to topicName with qos=2
unsubscribe R/W the client unsubscribes from topicName

Note 

All the subscriptions and unsubscriptions made at run-time are not persistent so they will be lost in case of driver restart.

All publish messages with QoS > 0 are temporarily stored in the directory "qos2store" waiting for the acknowledge by the MQTT broker. Once they are acknowledged they are deleted.