Tutorial: Connect a Device

Connect an OPC-UA server, model a piece of equipment as tags, and verify live values.

You will need: a running QUBIQ with a super-admin or editor login, and an OPC-UA server you can reach. Time: ~20 minutes.

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Step 1 — Discover the endpoint

Rather than guessing the security combination the server supports, ask it.

Connections → New connection → OPC-UA → Discover, and enter the base URL (opc.tcp://192.168.1.10:4840).

The response lists every endpoint the server advertises, with its security mode, policy and certificate. Pick one — the form fills itself in.

Different security, different URL

Servers usually advertise a different endpoint URL per security level. This is why "works with None, fails with SignAndEncrypt" is so common, and why discovery is the reliable route.

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Step 2 — Create the connection

Field	Value
Name	PLC1
Endpoint	From discovery
Security mode	None for now
Security policy	None for now
Username / Password	If the server requires them

Click Test. Green means QUBIQ reached the endpoint and authenticated. Save.

We will tighten security in step 6 — prove reachability first, so a later failure has one obvious cause.

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Step 3 — Browse the address space

Open the connection and choose Browse. QUBIQ walks the server's address space and shows the node tree with data types.

Find the equipment you want to model and note its NodeIds. Browse results carry the data type, which means QUBIQ can pre-fill your tags correctly instead of you guessing between int32 and float.

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Step 4 — Build the namespace

Namespace → New → Folder. Build the structure as the plant is laid out, not as the network is:

Site1/
  Line1/
    Filler/
      Motor1/

Then create tags inside Motor1:

Name	Data type	Unit	Description
Speed	float	RPM	Motor 1 shaft speed
Current	float	A	Motor 1 stator current
Running	boolean		Motor 1 running feedback
Fault	boolean		Motor 1 fault

Write the descriptions. They appear in pickers, tooltips and the AI assistant's context, and they are the difference between a model someone else can use and one only you understand.

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Step 5 — Bind the tags

For each tag: Binding → Add binding.

Field	Value
Connection	PLC1
Address	The NodeId from browse — or pick it from the tree
Polling mode	subscribe
Sampling rate	1000 ms
Deadband	0 for now

Save, and confirm Enabled is on.

Within a second or two the namespace shows live values with Good quality.

If quality is not Good

Quality	Meaning	Check
NotFound	The address does not exist	Typo, or the PLC program changed. Browse to confirm.
Bad	Read failed	Data-type mismatch, or insufficient rights on the node
Uncertain	Suspect	The server is reporting a degraded source

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Step 6 — Turn on security

Now that data flows, secure the link.

1. Discover again and pick a SignAndEncrypt / Basic256Sha256 endpoint.
2. Trust the server certificate — discovery returns it; trusting records its thumbprint, and a substituted certificate will then fail rather than silently connect.
3. Get QUBIQ trusted by the server. Most servers reject an unknown client on the first attempt and place its certificate in a rejected list. Move it to the trusted store on the server and retry. This is normal and happens once.
4. Test, and confirm tags return to Good.

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Step 7 — Tune

Now make it efficient.

Deadbands. Set 0.5–1% of span on the analogue tags. This removes sensor noise from the network, the historian and every screen at once.

Speed    eng 0–3000 RPM   → deadband 5 RPM
Current  eng 0–50 A       → deadband 0.1 A

Sampling rates. Match the value's real dynamics, not the maximum possible:

Speed    1000 ms      changes continuously
Current  1000 ms      changes continuously
Running  subscribe    changes rarely; push is free
Fault    subscribe    changes rarely; latency matters

Stale-after. For subscription tags, set stale-after to a few times the expected update interval. A value that never changes is otherwise indistinguishable from a dead link.

Scaling. If the server sends raw counts rather than engineering units, configure raw/eng ranges on the tag — once, here, instead of in every widget.

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Step 8 — Verify

• All four tags show Good quality
• Values change as the equipment runs
• The connection is healthy in the Connections list
• Security is SignAndEncrypt and still working
• Deadbands and sampling rates are set deliberately
• Descriptions and units are filled in

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What comes next

Next	Why
Build a dashboard	Put these tags on a screen
Alarm on a tag	React when Fault goes true
User-defined types	Do the next nineteen motors in minutes
Log data to SQL	Get this data into a report

Before the second motor, build a UDT

You have just defined the shape of "a motor". Turn it into a UDT now and the rest of the plant is parameters, not clicks. → User-defined types