Three substantive issues caught + fixed during the validation pass: 1. pymodbus rejects unknown keys at device-list / setup level. My PR 43 commit had `_layout_note`, `_uint16_layout`, `_bits_layout`, `_write_note` device-level JSON-comment fields that crashed pymodbus startup with `INVALID key in setup`. Removed all device-level _* fields. Inline `_quirk` keys WITHIN individual register entries are tolerated by pymodbus 3.13.0 — kept those in dl205.json since they document the byte math per quirk and the README + git history aren't enough context for a hand-author reading raw integer values. Documented the constraint in the top-level _comment of each profile. 2. pymodbus rejects sweeping `write` ranges that include any cell not assigned a type. My initial standard.json had `write: [[0, 2047]]` but only seeded HR[0..31] + HR[100] + HR[200..209] + bits[1024..1109] — pymodbus blew up on cell 32 (gap between HR[31] and HR[100]). Fixed by listing per-block write ranges that exactly mirror the seeded ranges. Same fix in dl205.json (was `[[0, 16383]]`). 3. pymodbus simulator stores all 4 standard Modbus tables in ONE underlying cell array — each cell can only be typed once (BITS or UINT16, not both). My initial standard.json had `bits[0..31]` AND `uint16[0..31]` overlapping at the same addresses; pymodbus crashed with `ERROR "uint16" <Cell> used`. Fixed by relocating coils to address 1024+, well clear of the uint16 entries at 0..209. Documented the layout constraint in the standard.json top-level _comment. Substantive driver bug fixed: ModbusTcpTransport.ConnectAsync was using `new TcpClient()` (default constructor — dual-stack, IPv6 first) then `ConnectAsync(host, port)` with the user's hostname. .NET's TcpClient default-resolves "localhost" to ::1 first, fails to connect to pymodbus (which binds 0.0.0.0 IPv4-only), and only then retries IPv4 — the failure surfaces as the entire ConnectAsync timeout (2s by default) before the IPv4 attempt even starts. PR 30's smoke test silently SKIPPED because the fixture's TCP probe hit the same dual-stack ordering and timed out. Both fixed: ModbusSimulatorFixture probe now resolves Dns.GetHostAddresses, prefers AddressFamily.InterNetwork, dials IPv4 explicitly. ModbusTcpTransport does the same — resolves first, prefers IPv4, falls back to whatever Dns returns (handles IPv6-only hosts in the future). This is a real production-readiness fix because most Modbus PLCs are IPv4-only — a generic dual-stack TcpClient would burn the entire connect timeout against any IPv4-only PLC, masquerading as a connection failure when the PLC is actually fine. Smoke-test address shifted HR[100] -> HR[200]. Standard.json's HR[100] is the auto-incrementing register that drives subscribe-and-receive tests, so write-then-read against it would race the increment. HR[200] is the first cell of a writable scratch range present in BOTH simulator profiles. DL205Profile.cs xml-doc updated to explain the shift; tag name "DL205_Smoke_HReg100" -> "Smoke_HReg200" + smoke test references updated. dl205.json gains a matching scratch HR[200..209] range so the smoke test runs identically against either profile. Validation matrix: - standard.json boot: clean (TCP 5020 listening within ~3s of pymodbus.simulator launch). - dl205.json boot: clean. - pymodbus client direct FC06 to HR[200]=1234 + FC03 read: round-trip OK. - raw-bytes PowerShell TcpClient FC06 + 12-byte response: matches FC06 spec (echo of address + value). - DL205SmokeTest against standard.json: 1/1 pass (was failing as 'BadInternalError' due to the dual-stack timeout + tag-name typo — both fixed). - DL205SmokeTest against dl205.json: 1/1 pass. - Modbus.Tests Unit suite: 52/52 pass — dual-stack transport fix is non-breaking. - Solution build clean. Memory + future-PR setup: pymodbus install + activation pattern is now bullet-pointed at the top of Pymodbus/README.md so future PRs (the per-quirk DL205_<behavior> tests in PR 44+) don't have to repeat the trial-and-error of getting the simulator + integration tests cooperating. The three bugs above are documented inline in the JSON profiles + ModbusTcpTransport so they don't bite again. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
LmxOpcUa
OPC UA server and cross-platform client tools for AVEVA System Platform (Wonderware) Galaxy. The server exposes Galaxy tags via MXAccess as an OPC UA address space. The client stack provides a shared library, CLI tool, and Avalonia desktop application for browsing, reading/writing, subscriptions, alarms, and historical data.
Architecture
OPC UA Clients
(CLI, Desktop UI, 3rd-party)
|
v
+-----------------+ +------------------+ +-----------------+
| Galaxy Repo DB |---->| OPC UA Server |<--->| MXAccess Client |
| (SQL Server) | | (address space) | | (STA + COM) |
+-----------------+ +------------------+ +-----------------+
| |
+-------+--------+ +---------+---------+
| Status Dashboard| | Historian Runtime |
| (HTTP/JSON) | | (SQL Server) |
+----------------+ +-------------------+
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 |
Server
The OPC UA server runs on .NET Framework 4.8 (x86) and bridges the Galaxy runtime to OPC UA clients.
Server 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) - Wonderware Historian (optional, for historical data access)
- Windows (required for COM interop and MXAccess)
Build and Run Server
dotnet restore ZB.MOM.WW.LmxOpcUa.slnx
dotnet build src/ZB.MOM.WW.LmxOpcUa.Host
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Host
The server starts on opc.tcp://localhost:4840/LmxOpcUa with the None security profile by default. Configure Security.Profiles in appsettings.json to enable Basic256Sha256-Sign or Basic256Sha256-SignAndEncrypt for transport security. See Security Guide.
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
Service logon requirement: The service must run under a Windows account that has access to the AVEVA Galaxy and Historian. The default LocalSystem account can connect to MXAccess and SQL Server but cannot authenticate with the Historian SDK (HCAP). Configure the service to "Log on as" a domain or local user that is a recognized ArchestrA platform user. This can be set in services.msc or during install with ZB.MOM.WW.LmxOpcUa.Host.exe install -username DOMAIN\user -password ***.
Run Server Tests
dotnet test tests/ZB.MOM.WW.LmxOpcUa.Tests
dotnet test tests/ZB.MOM.WW.LmxOpcUa.IntegrationTests
Client Stack
The client stack is cross-platform (.NET 10) and consists of three projects sharing a common IOpcUaClientService abstraction. No AVEVA software or COM is required — the clients connect to any OPC UA server.
Client Prerequisites
- .NET 10 SDK
- No platform-specific dependencies (runs on Windows, macOS, Linux)
Build All Clients
dotnet build src/ZB.MOM.WW.LmxOpcUa.Client.Shared
dotnet build src/ZB.MOM.WW.LmxOpcUa.Client.CLI
dotnet build src/ZB.MOM.WW.LmxOpcUa.Client.UI
Run Client Tests
dotnet test tests/ZB.MOM.WW.LmxOpcUa.Client.Shared.Tests
dotnet test tests/ZB.MOM.WW.LmxOpcUa.Client.CLI.Tests
dotnet test tests/ZB.MOM.WW.LmxOpcUa.Client.UI.Tests
Client CLI
# Connect
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- connect -u opc.tcp://localhost:4840/LmxOpcUa
# Browse Galaxy hierarchy
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- browse -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=3;s=ZB" -r -d 5
# Read a tag
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- read -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=3;s=TestMachine_001.MachineID"
# Write a tag
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- write -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=3;s=TestChildObject.TestString" -v "Hello"
# Subscribe to changes
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- subscribe -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=3;s=TestChildObject.TestInt" -i 500
# Read historical data
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- historyread -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=3;s=TestMachine_001.TestHistoryValue" --start "2026-03-25" --end "2026-03-30"
# Subscribe to alarm events
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- alarms -u opc.tcp://localhost:4840/LmxOpcUa -n "ns=3;s=TestMachine_001" --refresh
# Query redundancy state
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.CLI -- redundancy -u opc.tcp://localhost:4840/LmxOpcUa
Client UI
dotnet run --project src/ZB.MOM.WW.LmxOpcUa.Client.UI
The desktop application provides browse tree, subscriptions, alarm monitoring, history reads, and write dialogs. See Client UI Documentation for details.
Project Structure
src/
ZB.MOM.WW.LmxOpcUa.Host/ OPC UA server (.NET Framework 4.8, x86)
Configuration/ Config binding and validation
Domain/ Interfaces, DTOs, enums, mappers
Historian/ Wonderware Historian data source
Metrics/ Performance tracking (rolling P95)
MxAccess/ STA thread, COM interop, subscriptions
GalaxyRepository/ SQL queries, change detection
OpcUa/ Server, node manager, address space, alarms, diff
Status/ HTTP dashboard, health checks
ZB.MOM.WW.LmxOpcUa.Client.Shared/ Shared OPC UA client library (.NET 10)
ZB.MOM.WW.LmxOpcUa.Client.CLI/ Command-line client (.NET 10)
ZB.MOM.WW.LmxOpcUa.Client.UI/ Avalonia desktop client (.NET 10)
tests/
ZB.MOM.WW.LmxOpcUa.Tests/ Server unit + integration tests
ZB.MOM.WW.LmxOpcUa.IntegrationTests/ Server integration tests (live DB)
ZB.MOM.WW.LmxOpcUa.Client.Shared.Tests/ Shared library tests
ZB.MOM.WW.LmxOpcUa.Client.CLI.Tests/ CLI command tests
ZB.MOM.WW.LmxOpcUa.Client.UI.Tests/ UI ViewModel + headless tests
gr/ Galaxy repository docs, SQL queries, schema
Documentation
Server
| Component | Description |
|---|---|
| OPC UA Server | Endpoint, sessions, security policy, server lifecycle |
| Address Space | Hierarchy nodes, variable nodes, primitive grouping, NodeId scheme |
| Galaxy Repository | SQL queries, deployed package chain, change detection |
| MXAccess Bridge | STA thread, COM interop, subscriptions, reconnection |
| Data Type Mapping | Galaxy to OPC UA types, arrays, security classification |
| Read/Write Operations | Value reads, writes, access level enforcement, array element writes |
| Subscriptions | Ref-counted MXAccess subscriptions, data change dispatch |
| Alarm Tracking | AlarmConditionState nodes, InAlarm monitoring, event reporting |
| Historical Data Access | Historian data source, HistoryReadRaw, HistoryReadProcessed |
| Incremental Sync | Diff computation, subtree teardown/rebuild, subscription preservation |
| Configuration | appsettings.json binding, feature flags, validation |
| Status Dashboard | HTTP server, health checks, metrics reporting |
| Service Hosting | TopShelf, startup/shutdown sequence, error handling |
| Security | Transport security profiles, certificate trust, production hardening |
| Redundancy | Non-transparent warm/hot redundancy, ServiceLevel, paired deployment |
Client
| Component | Description |
|---|---|
| Client CLI | Connect, browse, read, write, subscribe, historyread, alarms, redundancy commands |
| Client UI | Avalonia desktop client: browse, subscribe, alarms, history, write values |
Reference
- Galaxy Repository Queries — SQL queries for hierarchy, attributes, and change detection
- Data Type Mapping — Galaxy to OPC UA type mapping with security classification
License
Internal use only.