Version: Next

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.

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.

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

Save. QUBIQ opens the connection, and its state shows in the Connections list — connected means it reached the endpoint and authenticated. There is no separate test step: the list shows the same signal that will tell you about this connection later.

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

Step 3 — Browse the address space

You will pick addresses from the server rather than type them. The browse button beside the address on a tag's Binding tab walks the server's address space and shows the node tree with data types. Browse results carry the data type, which means QUBIQ can pre-fill your tags correctly instead of you guessing between int32 and float.

For more than a handful of nodes, import them from the browse tree in one go instead. → Bulk import

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.

Step 5 — Bind the tags

For each tag, open it and go to the Binding tab. Switch on Enable Binding, then:

Field	Value
Protocol	OPC UA
Connection	`PLC1`
Address	Pick the node with the browse button beside the field

Save. OPC UA tags are subscribed — the server sends a value when it changes — with a 1000 ms publishing interval, so there is no rate to set. A tag has exactly one binding. → Protocol bindings

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.
`Unknown`	No value yet	Wait a moment. If it stays, check the binding is enabled.
`Bad`, waiting for initial data	Subscribed, first value not here yet	If it stays, the server is not serving that node.
`Bad`	Read failed	Data-type mismatch, or insufficient rights on the node
`Uncertain`	Suspect	The server is reporting a degraded source

Step 6 — Turn on security

Now that data flows, secure the link.

Discover again and pick a SignAndEncrypt / Basic256Sha256 endpoint.
Trust the server certificate — discovery returns it; trusting records its thumbprint, and a substituted certificate will then fail rather than silently connect.
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.
Test, and confirm tags return to Good.

Step 7 — Tune

Now make it efficient.

Engineering ranges. On each analogue tag's Scaling tab, set the Engineering range — 0–3000 RPM for Speed, 0–50 A for Current. If the server sends raw counts rather than engineering units, switch on Enable Scaling and give the raw range too: once, here, instead of in every widget.

Deadbands. On the History tab, set 0.5–1 % of span on the analogue tags — as units, or as % of range, which reads the engineering range. This keeps sensor noise out of the historian and off any broker you publish to.

Speed    eng 0–3000 RPM   → deadband 5 RPM    (or 0.2 % of range)
Current  eng 0–50 A       → deadband 0.1 A    (or 0.2 % of range)

Leave stale-after off here. An OPC UA subscription sends nothing while a value holds steady, so a motor that is simply not running would be marked stale. Stale after on the Binding tab is for sources that report on a cycle. A dead OPC UA server already turns its tags Bad through the connection. → Stale after

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
Engineering ranges and deadbands are set deliberately
Descriptions and units are filled in

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

Step 1 — Discover the endpoint​

Step 2 — Create the connection​

Step 3 — Browse the address space​

Step 4 — Build the namespace​

Step 5 — Bind the tags​

If quality is not Good​

Step 6 — Turn on security​

Step 7 — Tune​

Step 8 — Verify​

What comes next​