AzureMQTTClient (FB)

FUNCTION_BLOCK AzureMQTTClient

Function block to connect to Azure IoT Hub via MQTT.

InOut:

Scope

Name

Type

Initial

Comment

Input

xEnable

BOOL

TRUE: Opens a connection, FALSE: Close connection

uiKeepAlive

UINT

10

Keep alive interval in seconds (default: 10s)

tPingInterval

TIME

TIME#2s0ms

Ping interval (default: 2s)

udiTimeOut

UDINT

0

Defines the time (µs) after which the connection setup aborts with xError.

tReconnectTime

TIME

TIME#0ms

Time for an automatically reconnection, default is T#0s and reconnection is not acitve.

sHubDomainName

STRING(255)

Domain name of the IoT Hub

sDeviceId

STRING(255)

Device ID

wsSaS

WSTRING(255)

Shared Access Signature (SAS Token)

pbWillMessage

POINTER TO BYTE

0

Pointer to the ‚Last Will‘ message (optional)

uiWillMessageSize

UINT

0

Size of ‚Last Will‘ message (optional)

itfTLSContext

NBS.ITLSContext

0

Encapsulates all the data neccecray to handle encrypted tcp connections

Static initialization, as shown in the following code snippet.

VAR
    commonName : STRING := 'MyRrasPi';
    ciCertInfo : NBS.CERT_INFO := (psInfo:=ADR(commonName), udiSize:=LEN(commonName));
    myTLSContext : NBS.TLSContext := (
        ePurpose:=NBS.PURPOSE.CLIENT_SIDE,
        sUseCaseName:='NBSTest',
        sTLSVersion:='1.3',
        ciCertInfo:=ciCertInfo,
        udiVerificationMode:=2
    );
END_VAR

itfAsyncProperty

NBS.IAsyncProperty

0

Runs the connect process in a own background task. Use this property if the connection setup takes longer than one task cycle (e.g. TLS connections)

Output

xError

BOOL

TRUE, if an error occurred

xBusy

BOOL

TRUE, while the function block is active

eError

MQTT.MQTT_ERROR

The error id

xConnectedToBroker

BOOL

FALSE

FALSE when there is no connection to Azure IoT Hub, otherwise TRUE