Weidmüller u-OS Data Hub

The Weidmüller connector enables bidirectional data exchange between your logiccloud runtime and the Weidmüller u-OS Data Hub. You can publish PLC variables to the hub (provider) and subscribe to hub variables (consumer).

Note

To configure the IO station of a Weidmüller device — rather than exchange data with the hub — see the Device Editor.

Prerequisites

Before creating a Weidmüller connection, you need:

1. A Weidmüller u-OS device with the Data Hub enabled
2. OAuth2 client credentials configured in the u-OS Control Center (Identity & access → Clients)
3. The exact client name as shown in Control Center

Clients live in the device’s u-OS Control Center → Identity & access → Clients. Each has a Name and a Client ID; the Name column is the value the connector’s Client name field must match.

Creating the client

Press Add client and give it a Client name. The device states the rule beside the field: lower case a-z, 0-9 and _ are allowed, it must start with a letter, and it must not end with _.

Then tick the permissions the connector needs, under Variable HTTP API permissions:

Permission	Needed for
Read Hub variables	A consumer, which subscribes to hub variables
Provide Hub variables	A provider, which publishes to the hub
Read-and-write Hub variables	Mappings that write back to the hub (Mode To hub)

The Administration of API permissions below them — system information, logs, network, security and update settings — are not used by the connector. Leave them unticked.

u-OS shows the client secret once, when the client is created. Copy it then — you need it for the connection, and it cannot be read back afterwards.

Client Name Must Match Exactly

The Client Name you enter in logiccloud must match exactly what is configured in the u-OS Control Center. If it doesn’t match, connection requests will fail silently with no error message.

Silent Failures

The Weidmüller connector communicates with the u-OS Data Hub via NATS messaging. Due to how NATS addressing works, incorrect credentials or provider IDs cause silent timeouts — no error message is returned. If your connection appears stuck or variables aren’t updating:

1. Verify Client Name matches exactly (case-sensitive) what’s in u-OS Control Center
2. Verify Provider ID follows the naming rules (lowercase, starts with letter, no special characters)
3. Check edge device logs for registration or authentication errors

These are the most common causes of “nothing happens” scenarios.

Create a Weidmüller Connection

1. In your project, navigate to the Runtimes section
2. Select your runtime and expand Connections
3. Click Add connection and select Weidmüller
4. Fill in the connection details:

Field	Description
Connection name	A descriptive name for the connection
Connection description	Optional free text
OAuth2 client ID	The client ID from u-OS Control Center
Client name	The exact client name from u-OS Control Center
OAuth2 client secret	The client secret

Caution

Client name must match exactly what u-OS shows under Control Center → Identity & access → Clients. If it does not, connection requests fail silently.

There is no token-endpoint field: the edge derives it itself.

5. Click Save to create the connection

Add a Provider (Publish to Hub)

Providers publish PLC runtime variables to the u-OS Data Hub, making them available to other systems.

1. Right-click the connection and select Add Provider
2. Configure the provider:

Field	Description
Name	A descriptive name for the provider
Description	Optional free text
Label (optional)	Optional label for the provider
Folder	Optional prefix for variable addresses (dot-separated)

3. Click Save

Note

A provider has no identifier of its own. All providers of a connection appear on the device as one hub provider, named after the connection’s Client name. Use Folder to keep their variables apart — see Folder Prefix.

Hub Provider Name Rules

The name the hub sees comes from the connection’s Client name, so that value must follow the u-OS naming grammar:

• Lower case letters (a-z), digits (0-9) and underscores (_) only
• Must start with a letter
• Must not end with an underscore
• No dots, dashes, spaces or upper case letters

Valid: plc, weather_station, line1_sensors Invalid: PLC, plc-1, plc.line1, 1plc, plc_

u-OS enforces this as you type: the rule appears beside the Client name field when the value does not satisfy it.

Add a Consumer (Subscribe from Hub)

Consumers subscribe to u-OS Data Hub variables and write them to PLC runtime variables.

1. Right-click the connection and select Add Consumer
2. Give the consumer a Name and, optionally, a Description
3. Click Save

A consumer has no Label or Folder: those belong to providers, which publish.

Browse the Data Hub

Instead of typing addresses by hand, you can browse the address space the device actually reports and pick the variables you want.

1. Select the provider or consumer
2. Click Browse
3. Expand the folders and select one or more variables
4. Confirm — the IDE adds one mapping row per selected variable

The Browse Tree

The tree mirrors the folder model the hub reports. A dotted variable key such as digital_nameplate.address_information.city_town becomes one tree level per segment, so related variables stay grouped instead of appearing as one long flat list.

Folders and values are distinguished by what the device reports, not guessed:

• Folders can be expanded and contain other nodes.
• Values are the variables you can map.

A folder has no address of its own, so selecting one adds no mapping row. Select the values inside it instead.

What a Selected Variable Fills In

Column	Filled with
Variable Name	The full dotted key of the variable
Address	The bare dotted key — the only form the hub accepts
Type	The data type the device reports, defaulting to Bool if it reports none
Mode	From hub
Provider	The hub provider that owns the variable, when the device reports one

Variable Name is the full dotted key rather than only the last segment. Two variables named city_town in different folders therefore stay distinct instead of collapsing onto a single row.

The Provider is kept as its own field and is never joined onto the address. Leave it empty to inherit the endpoint’s Provider ID — see Per-Mapping Provider Override.

Access Levels and Mode

The hub reports whether each variable is read-only or read/write, and the Mode dropdown follows:

The device reports	Mode offers
Read-only	From hub only
Read/write	From hub and To hub

Writing to a read-only hub variable cannot succeed, so To hub is not offered for one — this prevents a mapping that fails silently at runtime.

Two details worth knowing:

• A browsed row always defaults to From hub, even when the variable is writable. Write access only unlocks the To hub option; it does not preselect it.
• A row you author by hand keeps both options, because nothing has told the IDE what that address supports.

Quality and Timestamp

The browse tree does not offer $quality or $timestamp entries. They are not variables you can map. Use the Quality Variable and Timestamp Variable fields on the mapping instead — see Quality and Timestamp Metadata.

Add Mappings

Mappings connect PLC variables to u-OS Data Hub variables.

1. Select the provider or consumer
2. Click Add Mapping
3. Configure each mapping:

Field	Description
Variable Name	The PLC runtime variable
Address	The hub variable address (dot-separated path)
Type	Data type: Bool, Int, Float64, String, etc.
Mode	Direction: From hub (subscribe) or To hub (publish)
Provider	Optional: override the endpoint’s provider ID for this mapping
Quality Variable	Optional: PLC variable for quality metadata
Timestamp Variable	Optional: PLC variable for timestamp metadata

Address Format

The hub variable address uses dot-separated segments:

Valid: temperature, line1.temp1, sensors.out.temp1 Invalid: 1temp, temp-1, temp/out

Folder Prefix

When you set a Folder on the provider/consumer, it is automatically prepended to each mapping’s address:

Folder	Mapping Address	Effective Address
sensors.out	temp1	sensors.out.temp1
plc.values	temperature	plc.values.temperature
(empty)	line1.sp1	line1.sp1

This allows organizing variables hierarchically without repeating the prefix in every mapping.

Data Types

Type	Description
Bool	Boolean (true/false)
Int	32-bit signed integer
Int64	64-bit signed integer
Float32	Single-precision floating point
Float64	Double-precision floating point
String	UTF-8 text
Duration	Time duration value
Timestamp	Date/time timestamp

Per-Mapping Provider Override

By default, all mappings in a provider/consumer use the endpoint’s Provider ID. You can override this per-mapping to publish/subscribe to a different hub provider:

1. In the mapping row, set the Provider field to a different provider ID
2. Leave it empty to inherit from the endpoint

This allows a single consumer to subscribe to variables from multiple hub providers.

Quality and Timestamp Metadata

Each mapping can optionally capture metadata reported by the u-OS Data Hub:

Field	Description
Quality Variable	A PLC variable that receives the hub-reported signal quality indicator. Useful for detecting stale or invalid data.
Timestamp Variable	A PLC variable that receives the hub-reported timestamp of the last value update. Useful for diagnostics and data synchronization.

These fields are optional. When configured, the edge runtime automatically populates them with metadata from the hub alongside the actual variable value.

Send and Receive Data

The sections above describe each field on its own. This is the whole task, end to end.

Data always travels between a PLC variable in your program and a hub variable on the device. A mapping is the link between the two, and its Mode says which way the value moves.

1. Declare the PLC variables

A mapping can only use a variable your program exposes. Declare it in the PLC code with the {IN} or {OUT} attribute, according to the direction you want:

Declared as	Becomes	Use it to
{IN}	an Input	receive a value from the hub
{OUT}	an Output	send a value to the hub

2. Refresh Inputs/Outputs

Open the runtime’s Inputs/Outputs and press Refresh. Newly declared variables appear only after this — the list does not update by itself.

3. Add a provider or a consumer

• To send data, add a provider. It publishes your PLC variables to the hub.
• To receive data, add a consumer. It subscribes to hub variables and writes them into your PLC variables.

4. Create the mappings

In the provider or consumer, add a mapping for each variable. Two shortcuts save typing:

• Browse picks the hub side — it fills Address, Type and Provider from what the device reports. See Browse the Data Hub.
• Advanced fill picks the PLC side — it opens Fill - Inputs/Outputs and creates a row per selected variable.

Advanced fill sets Mode from the variable’s direction: an Output becomes To hub, an Input becomes From hub. That is almost always what you want, and you can change it in the Mode column.

Caution

To hub is only offered for a hub variable the device reports as writable. A read-only hub variable can be read but never written — see Access Levels and Mode.

5. Deploy and check

Save the mappings, then build and deploy the runtime. Data starts moving once the runtime is running.

To confirm it, use the device’s own Data Hub Browser, below.

Check the Data on the Device

The device has its own u-OS Data Hub Browser, reached from the u-OS home page or directly at https://<DEVICE IP>/u-os-hub/. It lists every variable on the hub and shows each one’s current value, so it is the quickest way to confirm that a provider is publishing or that a consumer has something to read.

Select a variable in the tree and the right-hand pane shows it in full.

Every field there corresponds to something in this page:

In the Data Hub Browser	In logiccloud
Provider	The hub provider — named after your connection’s Client name
Key	The mapping Address — the bare dotted key
Access (Read-Only / Read-Write)	What the device reports, and therefore whether To hub is offered in Mode
Data type	The mapping Type
Current value	What your provider published, or what a consumer reads
Quality	What a Quality Variable receives
Latest change	What a Timestamp Variable receives

So if a mapping is not behaving as expected, this view answers three questions at once: whether the variable exists at all, whether the device considers it writable, and whether its value is actually changing.

Tip

A variable published by your own provider appears under the hub provider named after your Client name, with the Folder you set, if any, in front of its key.

Troubleshooting

Connection times out silently

Cause: The Client Name doesn’t match exactly what’s in u-OS Control Center.

Solution:

1. Open u-OS Control Center → Identity & access → Clients
2. Copy the exact client name (case-sensitive)
3. Update the connection in logiccloud

”providerId is not a valid hub provider name”

Cause: The Provider ID contains invalid characters.

Solution: Use only lowercase letters, digits, and underscores. Must start with a letter.

Variables not appearing in the hub

Possible causes:

• Provider not registered (check edge device logs)
• Address doesn’t match the VariableName grammar
• OAuth2 token expired or invalid

Solution:

1. Check the edge device logs for registration errors
2. Verify the address uses only valid characters (letters, digits, underscores, dots)
3. Verify OAuth2 credentials are correct

Mappings are empty after deployment

Cause: Mappings weren’t saved correctly.

Solution: Re-open the provider/consumer, verify mappings are listed, and save again.

A browsed item added no mapping row

Cause: The selected node has no mapping address. Folders are the usual case — they group variables but are not variables themselves.

Solution: Expand the folder and select the values inside it. If a value is skipped as well, the device reported no address for it; check the edge device logs.

To hub is missing from the Mode dropdown

Cause: The hub reported that variable as read-only, so only From hub is offered. Writing to it could not succeed.

Solution: If the variable should be writable, correct its access type in u-OS, then browse again so the IDE picks up the new access level.