AzureIoTHubOpen
- Last UpdatedOct 29, 2026
- 2 minute read
AzureIoTHubOpen creates a new Azure IoT Hub connection. See Notes for more information.
|
Function |
Group |
Execution |
String Exp. |
Windows |
Windows Embedded |
IoT View |
Thin Clients |
Mobile Access |
|---|---|---|---|---|---|---|---|---|
|
AzureIoTHubOpen |
Internet of Things |
Asynchronous |
No |
Supported |
Not supported |
Not supported |
Supported |
Supported |
Syntax
AzureIoTHubOpen(strAlias, strConfig)
strAlias
The name you want to give to the Azure IoT Hub connection that you are creating. This is the name that other functions will reference in order to use the connection.
strConfig
The configuration parameters for the Azure IoT Hubconnection. These parameter are listed in a single string enclosed in quotes with the format [parameter]=value separated by commas. The variables are:
|
Parameter Name |
Description |
|---|---|
|
Gateway |
IP address and port of the IoT Hub connection, using the format IP_Address:Port_Number |
|
Connection |
Connection string to IoT Hub. This value can be obtained from the IoT Hub portal. This is a semicolon-separated list of values including HostName, DeviceId, and SharedAccessKey. |
|
Transport |
The transport type, which has the following options: AMPQ, AMPQ_TCP_ONLY, AMQP_WEBSOCKET_ONLY, MQTT, MQTT_TCP_ONLY, MQTT_WEBSOCKET_ONLY, and HTTP1. |
|
USEPROXY |
Optional. Use value True if a web proxy is required to connect to IoT Hub host. |
|
PROXYADDRESS |
Optional. If using a web proxy, use the value of the address. Add a port number after a colon if appropriate. |
|
PROXYUSECREDENTIALS |
Optional. If the web proxy requires authentication, use value True. |
|
PROXYUSER |
Optional. Username if the web proxy requires authentication. |
|
PROXYPASSWORD |
Optional. Password if the web proxy require authentication. |
Return value
If successful, this function returns 0 (zero).
If unsuccessful, this function returns one of the following negative integer values:
|
Value |
Description |
|---|---|
|
-300 |
Invalid alias detected by server |
|
-301 |
Invalid connection parameter |
|
-302 |
Invalid message parameter |
|
-303 |
Invalid type parameter |
|
-304 |
Invalid property parameter |
|
-305 |
Invalid message ID parameter |
|
-306 |
Connection has not been defined |
|
-307 |
Conflicting alias |
|
-308 |
Open connection error |
|
-309 |
Invalid command |
|
-310 |
Communication error |
|
-311 |
Invalid parameter index |
Notes
Messages are kept in the Gateway ("alive" in the IoT Hub queue) for up to 10 minutes before they are deleted from the queue. (The settings for messages are currently configured in the IoT Hub settings.) The Gateway has a limit of 100 messages per connection; older messages (in terms of creation time) will be deleted to make room for newer messages.
Examples
As used in a Math worksheet:
|
Tag Name |
Expression |
|---|---|
|
nErr |
AzureIoTHubOpen ("Test","Connection=HostName=myhost.azure-devices.net;DeviceId=MyDevice;SharedAccessKey= fVxJl+ea7eh4nYp64Yub+E1n52uatVG0uyTuLqZIyKA=) |
|
nErr |
AzureIoTHubOpen ("Test","Gateway=127.0.0.1:3997,Transport=MQTT,Connection=HostName=myhost.azure-devices.net;DeviceId=MyDevice;SharedAccessKey= fVxJl+ea7eh4nYp64Yub+E1n52uatVG0uyTuLqZIyKA=) |