LmxOpcUa Server

OPC UA server on .NET Framework 4.8 (x86) that exposes AVEVA System Platform (Wonderware) Galaxy tags via the MXAccess toolkit. Mirrors the Galaxy object hierarchy as an OPC UA address space, translating between contained-name browse paths and tag-name runtime references.

Architecture

                                    OPC UA Clients
                                         |
                                         v
+-----------------+     +------------------+     +-----------------+
| Galaxy Repo DB  |---->|   OPC UA Server  |<--->| MXAccess Client |
|   (SQL Server)  |     | (address space)  |     | (STA + COM)     |
+-----------------+     +------------------+     +-----------------+
                                |
                        +-------+--------+
                        | Status Dashboard|
                        |  (HTTP/JSON)   |
                        +----------------+

Galaxy Repository queries the ZB database for the deployed object hierarchy and attribute definitions, building the OPC UA address space at startup and rebuilding on deploy changes.

MXAccess Client connects to the Galaxy runtime via COM interop on a dedicated STA thread with a Win32 message pump. Handles subscriptions, read/write, reconnection, and probe-based health monitoring.

OPC UA Server exposes the hierarchy as browse nodes (folders for areas, objects for containers) with variable nodes for each attribute. Clients browse using contained names but reads/writes translate to tag_name.AttributeName for MXAccess.

Contained Name vs Tag Name

Browse Path (contained names)	Runtime Reference (tag name)
TestMachine_001/DelmiaReceiver/DownloadPath	DelmiaReceiver_001.DownloadPath
TestMachine_001/MESReceiver/MoveInBatchID	MESReceiver_001.MoveInBatchID

Quick Start

Prerequisites

• .NET Framework 4.8 SDK
• AVEVA System Platform with ArchestrA Framework installed
• Galaxy repository database (SQL Server, Windows Auth)
• MXAccess COM registered (LMXProxy.LMXProxyServer)

Build & Run

dotnet restore ZB.MOM.WW.LmxOpcUa.slnx
dotnet build ZB.MOM.WW.LmxOpcUa.slnx
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Host

The server starts on opc.tcp://localhost:4840/LmxOpcUa with SecurityPolicy None.

Install as Windows Service

cd src/ZB.MOM.WW.LmxOpcUa.Host/bin/Debug/net48
ZB.MOM.WW.LmxOpcUa.Host.exe install
ZB.MOM.WW.LmxOpcUa.Host.exe start

Test with CLI Tool

# Connect
dotnet run --project tools/opcuacli-dotnet -- connect -u opc.tcp://localhost:4840/LmxOpcUa

# Browse Galaxy hierarchy
dotnet run --project tools/opcuacli-dotnet -- browse -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=1;s=ZB" -r -d 5

# Read a tag
dotnet run --project tools/opcuacli-dotnet -- read -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=1;s=TestMachine_001.MachineID"

# Write a tag
dotnet run --project tools/opcuacli-dotnet -- write -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=1;s=TestChildObject.TestString" -v "Hello"

# Subscribe to changes
dotnet run --project tools/opcuacli-dotnet -- subscribe -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=1;s=TestChildObject.TestInt" -i 500

Run Tests

dotnet test ZB.MOM.WW.LmxOpcUa.slnx

Configuration

All settings in appsettings.json, overridable via environment variables:

Section	Key	Default	Description
OpcUa	Port	4840	OPC UA server port
OpcUa	EndpointPath	/LmxOpcUa	Endpoint path
OpcUa	GalaxyName	ZB	Galaxy name (used in namespace URI)
OpcUa	MaxSessions	100	Maximum concurrent sessions
MxAccess	ClientName	LmxOpcUa	MXAccess registration name
MxAccess	AutoReconnect	true	Auto-reconnect on disconnect
MxAccess	ProbeTag	null	Tag for connection health probing
GalaxyRepository	ConnectionString	Server=localhost;Database=ZB;...	ZB database connection
GalaxyRepository	ChangeDetectionIntervalSeconds	30	Deploy change polling interval
Dashboard	Enabled	true	Enable HTTP status dashboard
Dashboard	Port	8081	Dashboard port

Project Structure

src/ZB.MOM.WW.LmxOpcUa.Host/
    Configuration/       Config binding and validation
    Domain/              Interfaces, DTOs, enums, mappers
    Metrics/             Performance tracking (rolling P95)
    MxAccess/            STA thread, COM interop, subscriptions
    GalaxyRepository/    SQL queries, change detection
    OpcUa/               Server, node manager, address space
    Status/              HTTP dashboard, health checks
    OpcUaService.cs      Service wiring (startup/shutdown)
    Program.cs           TopShelf entry point

tests/ZB.MOM.WW.LmxOpcUa.Tests/
    Configuration/       Config binding tests
    Domain/              Type mapping, quality, error code tests
    Metrics/             Performance metrics tests
    MxAccess/            STA thread, connection, subscription, R/W tests
    GalaxyRepository/    Change detection tests
    OpcUa/               Address space build/rebuild, data conversion tests
    Status/              Health check, dashboard, web server tests
    Wiring/              Component integration tests
    EndToEnd/            Full data flow smoke test

tools/opcuacli-dotnet/   OPC UA CLI test tool
gr/                      Galaxy repository docs, SQL queries, schema

Data Type Mapping

Galaxy Type	mx_data_type	OPC UA Type	NodeId
Boolean	1	Boolean	i=1
Integer	2	Int32	i=6
Float	3	Float	i=10
Double	4	Double	i=11
String	5	String	i=12
DateTime	6	DateTime	i=13
ElapsedTime	7	Double (seconds)	i=11
Reference	8	String	i=12
Enumeration	13	Int32	i=6
InternationalizedString	15	LocalizedText	i=21

Array attributes use ValueRank=1 with ArrayDimensions from the Galaxy attribute definition.

Startup Sequence

1. Load and validate configuration
2. Register AppDomain.UnhandledException handler
3. Create performance metrics
4. Connect MXAccess (STA thread + COM registration)
5. Start MXAccess monitor loop
6. Test Galaxy database connection
7. Start OPC UA server with programmatic config
8. Query hierarchy + attributes, build address space
9. Start change detection polling (rebuilds on deploy)
10. Start status dashboard (HTML + JSON + health endpoint)

License

Internal use only.