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Version: 1.0.0

OPC UA Client

The TwinEdge OPC UA Client is a free, cross-platform desktop application for browsing, testing, and debugging OPC UA servers.

Download​

PlatformDownloadRequirements
WindowsDownload (.exe)Windows 10+
macOSDownload (.dmg)macOS 11+

Features​

  • Browse OPC UA servers: Navigate namespace hierarchies
  • Read/Write values: Test data access
  • Monitor subscriptions: Real-time value updates
  • Certificate management: Handle security certificates
  • History access: Query historical data
  • Method calls: Execute server methods
  • Export data: Save data to CSV/JSON

Getting Started​

Installation​

Windows:

  1. Download the installer
  2. Run the .exe file
  3. Follow installation wizard
  4. Launch from Start Menu

macOS:

  1. Download the .dmg file
  2. Open and drag to Applications
  3. On first launch, right-click → Open (for Gatekeeper)

Linux:

  1. Download the AppImage
  2. Make executable: chmod +x TwinEdge-OPC-UA-Client.AppImage
  3. Run: ./TwinEdge-OPC-UA-Client.AppImage

Connecting to a Server​

  1. Click New Connection
  2. Enter server details:
    • Name: Friendly name
    • Endpoint URL: opc.tcp://192.168.1.100:4840
  3. Select security mode:
    • None: No encryption (testing only)
    • Sign: Message signing
    • SignAndEncrypt: Full security (recommended)
  4. Choose authentication:
    • Anonymous: No credentials
    • Username/Password: Enter credentials
    • Certificate: Select certificate file
  5. Click Connect

Browsing the Namespace​

Node Tree​

The left panel shows the OPC UA namespace tree:

Root
├── Objects
│   ├── Server
│   │   ├── ServerStatus
│   │   └── ServerCapabilities
│   └── DeviceSet
│       └── Pump_001
│           ├── Temperature
│           ├── Pressure
│           └── FlowRate
├── Types
└── Views

Node Details​

Click a node to see:

  • Node ID: Unique identifier
  • Browse Name: Display name
  • Node Class: Variable, Object, Method, etc.
  • Data Type: For variables
  • Value: Current value (if readable)
  • Attributes: All OPC UA attributes

Searching Nodes​

Use the search bar to find nodes:

  • Search by browse name
  • Search by node ID
  • Filter by node class

Reading and Writing Values​

Reading Values​

  1. Navigate to a Variable node
  2. Click Read to get current value
  3. View in the Details panel

Or right-click → Read Value

Writing Values​

  1. Navigate to a Variable node
  2. Click Write
  3. Enter new value in dialog
  4. Click Write to send

Bulk Operations​

Read/write multiple values:

  1. Select multiple nodes (Ctrl+Click)
  2. Right-click → Read Selected
  3. View results in table

Subscriptions​

Creating a Subscription​

Monitor values in real-time:

  1. Navigate to variables to monitor
  2. Right-click → Add to Subscription
  3. Configure subscription:
    • Publishing Interval: Update frequency (ms)
    • Sampling Interval: Server sampling rate
    • Queue Size: Queued values per notification

Subscription Panel​

The subscription panel shows:

  • Current value
  • Value timestamp
  • Status code
  • Update indicator

Exporting Subscription Data​

  1. Start subscription
  2. Let data collect
  3. Click Export
  4. Choose format (CSV/JSON)
  5. Save file

Certificate Management​

Generating Certificates​

Create a new client certificate:

  1. Go to Tools → Certificates
  2. Click Generate New
  3. Fill in details:
    • Common Name: Your identifier
    • Organization: Company name
    • Validity: 1-5 years
  4. Click Generate

Trusting Server Certificates​

When connecting to a secured server:

  1. If certificate is untrusted, you'll see a prompt
  2. Review certificate details
  3. Click Trust to add to trusted store
  4. Or Trust Once for single session

Managing Certificate Store​

View and manage certificates:

  1. Go to Tools → Certificates
  2. Tabs:
    • Own: Your client certificates
    • Trusted: Trusted server certificates
    • Rejected: Previously rejected certificates

Historical Data​

Reading History​

Query historical values:

  1. Navigate to a variable with history
  2. Right-click → Read History
  3. Configure query:
    • Start Time: Begin timestamp
    • End Time: End timestamp
    • Max Values: Limit results
  4. Click Read
  5. View results in table

Charting Historical Data​

  1. Read historical data
  2. Click Chart icon
  3. View trend chart
  4. Adjust time range
  5. Export as image

Method Calls​

Calling Methods​

Execute OPC UA methods:

  1. Navigate to a Method node
  2. Right-click → Call Method
  3. Enter input arguments
  4. Click Call
  5. View output arguments

Method Details​

View method signature:

  • Input arguments (name, type, description)
  • Output arguments
  • Parent object

Data Export​

Export Options​

Export data in various formats:

FormatUse Case
CSVSpreadsheet analysis
JSONProgrammatic processing
XMLOPC UA NodeSet format

Exporting Node Data​

  1. Select nodes to export
  2. Right-click → Export
  3. Choose format
  4. Select data to include:
    • Node metadata
    • Current values
    • Subscription history
  5. Save file

Discovery​

Discovering Servers​

Find OPC UA servers on the network:

  1. Go to Discovery → Find Servers
  2. Enter discovery URL or use network scan
  3. View found servers
  4. Double-click to connect

Server Endpoints​

View available endpoints:

  1. Connect with discovery URL
  2. Go to Connection → Get Endpoints
  3. View security options
  4. Select and connect

Settings​

Connection Settings​

  • Timeout: Connection timeout (seconds)
  • Session Timeout: Requested session timeout
  • Max References: Browse limit per call
  • Auto Reconnect: Reconnect on disconnect

Display Settings​

  • Theme: Light/Dark mode
  • Date Format: Timestamp display
  • Decimal Places: Value precision
  • Show Status Bar: Toggle status bar

Certificate Settings​

  • Certificate Store Path: Location of certificates
  • Trust All Certificates: Disable verification (testing only)
  • Auto-Generate Certificate: Create on first run

Keyboard Shortcuts​

ShortcutAction
Ctrl+NNew connection
Ctrl+RRead selected value
Ctrl+WWrite value
Ctrl+SAdd to subscription
F5Refresh tree
Ctrl+FSearch nodes
Ctrl+EExport

Troubleshooting​

Connection Issues​

"BadTimeout" Error:

  • Increase connection timeout
  • Check network connectivity
  • Verify server is running

"BadCertificateUntrusted":

  • Trust the server certificate
  • Check certificate validity
  • Verify certificate chain

"BadUserAccessDenied":

  • Check username/password
  • Verify user permissions
  • Check security policy

Performance Issues​

Slow Browse:

  • Reduce max references per call
  • Collapse unused tree branches
  • Filter by node class

High Memory:

  • Reduce subscription queue size
  • Clear old subscription data
  • Limit historical queries

Support​

License​

The TwinEdge OPC UA Client is free for commercial and personal use. See LICENSE.txt for details.

Next Steps​