Technology

OPC UA integration: server discovery, certificates and secure reads

We connect securely to the OPC UA servers in your plant, place their nodes in a meaningful data model and deliver them to production systems.

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Our clients

Siemens
Anadolu Isuzu
BSH
Tofaş
Toyotetsu
Martur
Turkcell
Vodafone
Doğadan
Pakmaya
Bross
Abdi İbrahim
Nobel İlaç
Plastimak
Dalgıç Kalıp
Barbaros Motor
Magneti Marelli
Rözmaş
Sanel

OPC UA is an open standard for secure, vendor-independent data exchange between industrial devices and software. Many systems now expose an OPC UA server, from the S7-1200 and S7-1500 server enabled in TIA Portal to TwinCAT and CODESYS-based controllers and SCADA software.

The hard part of OPC UA integration is not the connection but the order around it: which servers run in which security mode, who trusts which certificates, which of the hundreds of nodes in the address space are actually needed, and how they are named.

VOLSOFT makes these decisions with the plant's automation and IT teams and sets up the reading on Proxus. We do not configure the PLC or software that publishes the server; we specify the settings needed and verify them.

What we deliver

OPC UA integration

Server discovery

OPC UA servers on the network are found by trying opc.tcp 4840 and 53530 and opc.https 53443. A server address can also be entered by hand.
Security modes and certificates

We connect with the security mode the server offers: None, Sign or Sign & Encrypt. Server certificates are trusted on the central server, and we recommend encrypted modes in production.
Address-space browsing

We browse the server's address space folder by folder and pick nodes. The data type comes from the node, so NodeIds are never typed by hand.
Polling versus subscriptions

Proxus reads OPC UA devices by polling all their tags together at a set read interval; it does not use OPC UA subscriptions. For signals where short changes matter, we set the interval accordingly.
Moving from Kepware

If Kepware runs in the plant, its OPC UA client channels can be imported into Proxus with nothing changed on the Kepware side.

How a project runs

From discovery to live, step by step

01
Server inventory

We list the plant's OPC UA servers, their versions, security policies and the network zone each sits in.
02
Security and certificate plan

With IT and automation we decide which server connects in which mode and who approves certificates.
03
Node selection and modeling

We pick the needed nodes and place them in the shared data model with ISA-95-style names.
04
Commissioning

We start reading, compare values with the source system and connect MES, historian or ERP.

Built on Proxus

Proxus connects to OPC UA servers from the edge gateway. The wizard finds servers, certificate trust is managed on the central server, and selected nodes flow into the Unified Namespace and on to MQTT, SQL Server or the cloud.

Proxus is the industrial data platform built by the VOLSOFT team.

Proxus OPC UA driver ↗

Frequently asked questions

Common questions

What is OPC UA?

OPC UA (Open Platform Communications Unified Architecture) is an open standard for secure, vendor-independent data exchange between industrial devices and software. It exposes data in a typed, hierarchical address space and includes certificate-based security.

How is the OPC UA server on an S7-1500 used?

On S7-1200 and S7-1500 CPUs the OPC UA server is enabled in TIA Portal and the variables to publish are selected. Firmware and licensing conditions vary by CPU; the plant's automation team makes the settings and we specify and verify them.

What are the OPC UA security modes?

There are three: None, Sign (messages are signed) and Sign & Encrypt (signed and encrypted). Signed and encrypted modes require certificate trust, and we recommend them in production.

What is the difference between OPC UA and MQTT?

OPC UA is a client-server standard with rich types and address structure for reading devices and servers. MQTT is a lightweight publish-subscribe protocol that distributes data to many consumers through a broker. A typical design reads with OPC UA and distributes with MQTT.

Should we use OPC UA subscriptions or polling?

Subscriptions suit short-lived changes when the server handles them well; polling suits predictability. Proxus reads OPC UA devices by polling at a configured interval.