Routed by tia-openness-roadmap. C# Openness implementation of PLC software engineering: program blocks, system blocks, PLC tags and tag tables, user data types, external sources, watch and force tables, technology objects, software units, know-how protection, SafetyAdministration, PLC online/offline control, download, upload, compare-to-online, PLC compile, PLC import/export, master secret, and certificate/security services.

tia-plc-operations

Scope

PLC software engineering — full C# Openness implementation.

When the roadmap routes here, the entire solution is C#. Do not mix with Python wrapper calls. Always load tia-csharp-common first (done by roadmap).

Reference files

Load ONLY the reference file(s) relevant to the task. Do not load all files at once.

Reference file	Load when the task involves
`references/online-status.md`	Going online/offline, reading PLC state, configuring connection parameters, `OnlineProvider`, `OnlineState`, `ConnectionConfiguration`
`references/compare.md`	Comparing PLC software or hardware, `CompareResult`, `CompareResultState`, `CompareToOnline`, `UpdateProgram`
`references/blocks.md`	Program blocks, system blocks, external sources, know-how/write protection, block groups, ProDiag-FB, DataBlock snapshots, compile individual block/UDT, fingerprints, webserver pages, OB priority, loadable file
`references/tags-types.md`	PLC tag tables, tags, user constants, system constants, UDT group navigation
`references/software-units.md`	Software units (`PlcUnit`), `PlcUnitProvider`, unit relations, unit access/publish, external sources in units, units as mastercopies, namespaces, name value type documents, loadable file for units
`references/safety-unit.md`	Fail-safe unit (`PlcSafetyUnit`), SafetyUnit access, safety relations, publish safety blocks, supervision export/import

For tasks spanning multiple areas, load all relevant reference files before generating code.

Stub behaviour

If a task targets a partial reference file, do not invent API calls. State clearly which sections are missing. The only remaining stub is import/export signatures in compile-import-export.md — all other files are complete.

Execution pattern

Access PlcSoftware via device's SoftwareContainer
Identify which reference file(s) cover the task — load them
Navigate Openness object model per reference file patterns
For online work: use OnlineProvider service on the CPU DeviceItem (see online-status.md)
For compare: use CompareTo / CompareToOnline on PlcSoftware or Device (see compare.md)
For software units: access via PlcUnitProvider service on PlcSoftware (see software-units.md)
For safety unit: access via PlcUnitProvider.UnitGroup.SafetyUnits (see safety-unit.md)

Access pattern (always needed)

using Siemens.Engineering.HW.Features;
using Siemens.Engineering.SW;

// From a DeviceItem (CPU)
SoftwareContainer sc = deviceItem.GetService<SoftwareContainer>();
PlcSoftware plcSoftware = sc?.Software as PlcSoftware;