tia-sivarc

Scope

Use this skill for SiVArc engineering through the V21 C# Openness API.

• Assembly: Siemens.Engineering.Sivarc.dll
• Namespace: Siemens.Engineering.SiVArc (the namespace capitalization differs from the assembly filename)
• Entry point: Sivarc sivarc = project.GetService<Sivarc>()
• Prerequisite: load tia-csharp-common first

Do not substitute WinCC/HMI APIs for SiVArc rule or generation APIs. SiVArc generation creates, updates, renames, and may remove generated HMI objects; it is a live project mutation, not a read-only build step.

Reference files

Load only the reference required by the task.

Reference	Use for
references/generation.md	SiVArc license and generation preflight; exact GenerationOptions; result and recursive message handling
references/rules-and-libraries.md	All six rule families; tables, folders, groups, rules; library copies, type instances, and dynamic device columns
references/definitions-expression-layout.md	Tag/text definitions, tag member settings, definition upgrade, expression resolution, and screen layout YML import/export
references/api-catalogue.md	Complete inventory of all 92 installed V21 public SiVArc types

V21 service acquisition

using Siemens.Engineering;
using Siemens.Engineering.SiVArc;

Sivarc sivarc = project.GetService<Sivarc>();
if (sivarc == null)
    throw new InvalidOperationException("SiVArc is unavailable for the selected project or installation.");

Any modification of SiVArc data, including generation, requires a valid SiVArc license. V21 reports a missing license as a recoverable LicenseNotFound exception; do not convert that into a successful no-op.

Safety boundary

• Require explicit authorization for the exact project, HMI runtime/device names, PLC device names, rule objects, generation options, and mutation type.
• Resolve every table, folder, group, rule, block, screen, and library item by an exact selector. Fail on zero or ambiguous matches; never use .First(), index zero, or a silent fallback to a default table.
• Before generation, inventory the HMI-to-PLC connections, source PLC compile status, previous/frozen generation selection, rules included by the selected flags, and generated objects that may be replaced or removed.
• GenerationOptions.None means “use project settings”; it is not a preview or dry run. CreateOptions.Replace can overwrite an existing object.
• Imports, rule expressions, dynamic attribute names, library objects, and YML files are untrusted engineering input. Validate path, provenance, identity, and destination.
• Inspect returned result objects and recursive feedback. Exceptions and error counts fail the operation. Never infer success from a non-null return value.
• Do not claim generation rollback from a transaction without live V21 evidence. Use ExclusiveAccess for mutations and only use a transaction for calls proven compatible with it.
• Do not save the project unless persistence was explicitly requested. If validation fails, leave the project unsaved and report that live recovery/rollback was not proven.

Execution pattern

1. Load tia-csharp-common and this skill.
2. Open or attach to the exact project and acquire Sivarc.
3. Perform a read-only inventory and resolve exact identities.
4. State the effective rule/generation scope and destructive consequences.
5. Obtain explicit authorization for the mutation.
6. Acquire ExclusiveAccess, perform the smallest operation, and capture all results/exceptions.
7. Compile or validate affected PLC/HMI artifacts where the API supports it.
8. Save only when explicitly requested and verification passed.

Evidence boundary

Static inspection against Siemens.Engineering.Sivarc.xml and reflection proves names and signatures only. License availability, project compatibility, generation behavior, retained manual edits, station-selection state, and produced HMI objects require an authorized live TIA Portal V21 run.