Dahlke.TwinCAT.Ads documentation

A .NET library for TwinCAT ADS with durable connections, typed symbol access, simulation mode, and ASP.NET Core integration. Install and quick start are in the README; this is the long-form documentation.

Something is failing and you have the error text? Start at Troubleshooting — it is indexed by the error you see, likeliest cause first.

Page	What it covers
Connections	The connection pool, the no-host builder for console/WPF/WinForms, connection lookup and keyed injection, connection state, wait-then-throw semantics, and per-call timeouts with WithTimeout
Reading and writing values	Typed reads and writes, binding PLC structs to .NET types, PlcSymbol<T> handles, batch operations, RPC method calls, symbol browsing, and the IEC 61131-3 type mapping
Subscriptions	Durable value-change subscriptions, notification metadata, and the Rx companion package
PLC alarms	The Dahlke.TwinCAT.Ads.Alarms package: tracking a TwinCAT alarm array, transition handlers, acknowledgement over ADS, restart semantics, and fault tolerance
Raw ADS channels	Index-group/index-offset access for targets the symbol API cannot reach — EtherCAT masters, the system service — with durable notifications and a seedable simulation store
Simulation	Per-target and whole-fleet simulation, seeding initial values from code and configuration
Testing	The Dahlke.TwinCAT.Ads.Testing harness (TestPlc, write assertions) and hand-written doubles via AdsConnectionBase
Configuration reference	Every configuration section — AmsRouter, PlcTargets, RawChannels, AdsSymbolDump, PlcAlarms — with defaults and validation rules, plus health checks
Troubleshooting	Indexed by the error text you see, likeliest cause first

The API reference, generated from the XML documentation of every public member, is published at patdhlk.com/Dahlke.TwinCAT.Ads.

The three EtherCAT packages document themselves on their own package pages: Dahlke.EtherCAT.Diagnostics, Dahlke.EtherCAT.Esi and Dahlke.EtherCAT.Cia402.