Restructure the driver-facing docs to match the OtOpcUa v2 multi-driver
reality (Galaxy, Modbus, S7, AB CIP, AB Legacy, TwinCAT, FOCAS, OPC UA Client
— 8 drivers total; Galaxy ships as three projects) and the capability-interface
architecture where every driver opts into IDriver + whichever of IReadable /
IWritable / ITagDiscovery / ISubscribable / IHostConnectivityProbe /
IPerCallHostResolver / IAlarmSource / IHistoryProvider / IRediscoverable it
supports. Doc scope follows the code: one-driver-specific docs scoped to that
driver, cross-driver concerns live once at the top level, per-driver specs
cross-link to docs/v2/driver-specs.md rather than duplicate.
What changed per file:
- docs/MxAccessBridge.md -> docs/drivers/Galaxy.md (git mv + rewrite): retitled
"Galaxy Driver", reframed as one of seven drivers. Added Project Split table
(Shared .NET Standard 2.0 / Host .NET 4.8 x86 / Proxy .NET 10) and Why
Out-of-Process section citing both the MXAccess bitness constraint and Tier C
stability isolation per docs/v2/plan.md section 4. Added IPC Transport
section covering pipe naming, MessagePack framing, DACL that denies Admins,
shared-secret handshake, heartbeat, and CallAsync<TReq,TResp> dispatch.
Moved file paths from src/ZB.MOM.WW.LmxOpcUa.Host/MxAccess/* to
src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host/Backend/MxAccess/* and added the
Shared + Proxy key-file tables. Added CapabilityInvoker + OTOPCUA0001
analyzer callout. Cross-linked to drivers/README.md, Galaxy-Repository.md,
HistoricalDataAccess.md.
- docs/GalaxyRepository.md -> docs/drivers/Galaxy-Repository.md (git mv +
rewrite): retitled "Galaxy Repository — Tag Discovery for the Galaxy
Driver", opened with a comparison table showing how every driver's
ITagDiscovery source is different (AB CIP @tags walker, TwinCAT
SymbolLoaderFactory, FOCAS CNC queries, OPC UA Client Session.Browse, etc).
Repositioned GalaxyRepositoryService as the Galaxy driver's
ITagDiscovery.DiscoverAsync implementation. Updated paths to
Driver.Galaxy.Host/Backend/GalaxyRepository/*. Added IRediscoverable section
covering the on-change-redeploy IPC path.
- docs/drivers/README.md (new): index with ground-truth driver table —
project path, stability tier, wire library, capability-interface list, and
one notable quirk per driver. Verified against the driver csproj files and
class declarations on focas-pr3-remaining-capabilities (the most recent
branch containing every driver). Galaxy gets its own dedicated docs; the
other seven drivers cross-link to docs/v2/driver-specs.md. Lists the full
Core.Abstractions capability surface, DriverTypeRegistry, CapabilityInvoker,
and OTOPCUA0001 analyzer.
- docs/HistoricalDataAccess.md (rewrite): reframed around IHistoryProvider as
a per-driver optional capability interface. Replaced v1 HistorianPluginLoader
/ AvevaHistorianPluginEntry plugin architecture with the v2 story —
Historian.Aveva was merged into Driver.Galaxy.Host/Backend/Historian/ and
IPC-forwarded through GalaxyProxyDriver. Documented all four IHistoryProvider
methods (ReadRawAsync / ReadProcessedAsync / ReadAtTimeAsync /
ReadEventsAsync), CapabilityInvoker wrapping with DriverCapability.HistoryRead,
and the per-driver coverage matrix (Galaxy + OPC UA Client implement; the
six protocol drivers don't and return BadHistoryOperationUnsupported). Kept
the cluster-failover + health-counter + quality-mapping detail for the
Galaxy Historian implementation. Flagged one gap: Proxy forwards all four
history message kinds but the Host-side HistoryAggregateType -> AnalogSummary
column mapping may surface GalaxyIpcException{Code="not-implemented"} on a
given branch until the Phase 2 Galaxy out-of-process gate lands.
Driver list built against ground truth (src on focas-pr3-remaining-capabilities):
Driver.Galaxy.{Shared,Host,Proxy}, Driver.Modbus, Driver.S7, Driver.AbCip,
Driver.AbLegacy, Driver.TwinCAT, Driver.FOCAS, Driver.OpcUaClient.
Capability interface lists verified against each *Driver.cs class declaration.
Aveva Historian ported to Driver.Galaxy.Host/Backend/Historian/; no separate
Historian.Aveva assembly on v2 branches.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
OtOpcUa documentation
Two tiers of documentation live here:
- Current reference at the top level (
docs/*.md) — describes what's shipped today. Start here for operator + integrator reference. - Implementation history + design notes at
docs/v2/*.md— the authoritative plan + decision log the current reference is built from. Start here when you need the why behind an architectural choice, or when a top-level doc says "see plan.md § X".
The project was originally called LmxOpcUa (a single-driver Galaxy/MXAccess OPC UA server) and has since become OtOpcUa, a multi-driver OPC UA server platform. Any lingering LmxOpcUa-string in a path you see in docs is a deliberate residual (executable name lmxopcua-cli, client PKI folder {LocalAppData}/LmxOpcUaClient/) — fixing those requires migration shims + is tracked as follow-ups.
Platform overview
- Core owns the OPC UA stack, address space, session/security/subscription machinery.
- Drivers plug in via capability interfaces in
ZB.MOM.WW.OtOpcUa.Core.Abstractions:IDriver,IReadable,IWritable,ITagDiscovery,ISubscribable,IHostConnectivityProbe,IAlarmSource,IHistoryProvider,IPerCallHostResolver. Each driver opts into whichever it supports. - Server is the OPC UA endpoint process (net10, x64). Hosts every driver except Galaxy in-process; talks to Galaxy via a named pipe because MXAccess COM is 32-bit-only.
- Admin is the Blazor Server operator UI (net10, x64). Owns the Config DB draft/publish flow, ACL + role-grant authoring, fleet status +
/metricsscrape endpoint. - Galaxy.Host is a .NET Framework 4.8 x86 Windows service that wraps MXAccess COM on an STA thread for the Galaxy driver.
Where to find what
Architecture + data-path reference
| Doc | Covers |
|---|---|
| OpcUaServer.md | Top-level server architecture — Core, driver dispatch, Config DB, generations |
| AddressSpace.md | GenericDriverNodeManager + ITagDiscovery + IAddressSpaceBuilder |
| ReadWriteOperations.md | OPC UA Read/Write → CapabilityInvoker → IReadable/IWritable |
| Subscriptions.md | Monitored items → ISubscribable + per-driver subscription refcount |
| AlarmTracking.md | IAlarmSource + AlarmSurfaceInvoker + OPC UA alarm conditions |
| DataTypeMapping.md | Per-driver DriverAttributeInfo → OPC UA variable types |
| IncrementalSync.md | Address-space rebuild on redeploy + sp_ComputeGenerationDiff |
| HistoricalDataAccess.md | IHistoryProvider as a per-driver optional capability |
Drivers
| Doc | Covers |
|---|---|
| drivers/README.md | Index of the seven shipped drivers + capability matrix |
| drivers/Galaxy.md | Galaxy driver — MXAccess bridge, Host/Proxy split, named-pipe IPC |
| drivers/Galaxy-Repository.md | Galaxy-specific discovery via the ZB SQL database |
For Modbus / S7 / AB CIP / AB Legacy / TwinCAT / FOCAS / OPC UA Client specifics, see v2/driver-specs.md.
Operational
| Doc | Covers |
|---|---|
| Configuration.md | appsettings bootstrap + Config DB + Admin UI draft/publish |
| security.md | Transport security profiles, LDAP auth, ACL trie, role grants, OTOPCUA0001 analyzer |
| Redundancy.md | RedundancyCoordinator, ServiceLevelCalculator, apply-lease, Prometheus metrics |
| ServiceHosting.md | Three-process deploy (Server + Admin + Galaxy.Host) install/uninstall |
| StatusDashboard.md | Pointer — superseded by v2/admin-ui.md |
Client tooling
| Doc | Covers |
|---|---|
| Client.CLI.md | lmxopcua-cli — command-line client |
| Client.UI.md | Avalonia desktop client |
Requirements
| Doc | Covers |
|---|---|
| reqs/HighLevelReqs.md | HLRs — numbered system-level requirements |
| reqs/OpcUaServerReqs.md | OPC UA server-layer reqs |
| reqs/ServiceHostReqs.md | Per-process hosting reqs |
| reqs/ClientRequirements.md | Client CLI + UI reqs |
| reqs/GalaxyRepositoryReqs.md | Galaxy-scoped repository reqs |
| reqs/MxAccessClientReqs.md | Galaxy-scoped MXAccess reqs |
| reqs/StatusDashboardReqs.md | Pointer — superseded by Admin UI |
Implementation history (docs/v2/)
Design decisions + phase plans + execution notes. Load-bearing cross-references from the top-level docs:
- v2/plan.md — authoritative v2 vision doc + numbered decision log (referenced as "decision #N" elsewhere)
- v2/admin-ui.md — Admin UI spec
- v2/acl-design.md — data-plane ACL + permission-trie design (Phase 6.2)
- v2/config-db-schema.md — Config DB schema reference
- v2/driver-specs.md — per-driver addressing + quirks for every shipped protocol
- v2/dev-environment.md — dev-box bootstrap
- v2/test-data-sources.md — integration-test simulator matrix (includes the pinned libplctag
ab_serverversion for AB CIP tests) - v2/implementation/phase--.md — per-phase execution plans with exit-gate evidence