MQTT_Bridge (FB)

FUNCTION_BLOCK MQTT_Bridge EXTENDS CBML.LConTo IMPLEMENTS IExponentialBackoff

Function Block to connect to the Google Cloud Iot Core over the MQTT Bridge

InOut:

Scope

Name

Type

Initial

Comment

Inherited from

Input

xEnable

BOOL

TRUE: Activates the defined operation FALSE: Aborts/resets the defined operation

LConTo

udiTimeOut

UDINT

Max. operating time for executing [µs], 0: No operating time limit

LConTo

Output

xDone

BOOL

TRUE: Ready condition reached

LConTo

xBusy

BOOL

TRUE: Operation is running

LConTo

xError

BOOL

TRUE: Error condition reached

LConTo

Input

sproject_id

STRING(255)

PROJECT_ID used by Google IoT CORE

scloud_region

STRING(255)

REGION used by Google IoT CORE

sregistry_id

STRING(255)

REGISTRY_ID used by Google IoT CORE

sdevice_id

STRING(255)

DEVICE_ID used by Google IoT CORE

sCommonNamePrivateKey

STRING

Common Nmae of privat key certificate

sUseCaseNamePrivateKey

STRING

Use Case Name of certificats

udiJWTExpirationTime

UDINT

3600

Expiration Time of the JWT, in [s]. Default 3600 s

smqtt_bridge_hostname

STRING(255)

‘mqtt.googleapis.com’

Used MQTT Hostname. Default ‘mqtt.googleapis.com’

uimqtt_bridge_port

UINT

8883

Used MQTT Bridge port. Default 8883

uiKeepAlive

UINT

60

Keep alive Time in [s]. Default 60 s

uimaximum_backoff_Time

UINT

3200

Maximum Backoff time allowed in [ms]. Default is 3200 ms

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)

sSNTPServer

REFERENCE TO STRING(255)

The IP address or the name of a SNTP server to get the UTC time. If the input is not set, then the local system time will be used.

Output

eError

Error

Output Error

eMQTTError

MQTT.MQTT_ERROR

Error from MQTT

xConnected

BOOL

Connected to Cloud Broker

Methods:

Structure: