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Manufacturer data as first-class citizen: FDD system

Betrifft: ForgeIEC Studio

What it’s about

Manufacturer data in automation is classically a distribution problem: the data sheet lives as a PDF on a network drive, the GSD/EDS/FDD file in another folder, and the diagnostic-bit table in the appendix of the user manual — if not already lost.

ForgeIEC Studio treats the manufacturer’s FDD as the binding source and packs everything together: machine-readable device description plus the PDF data sheet plus the diagnostic-bit tables — all in one file, all accessible from Studio.

One file, everything inside

The FDD is held in the PLCopen FDD XML format. Data sheets land as CDATA-embedded PDFs in the <Document> element. On import Studio detects this, extracts the PDF, shows it in the documents tab of the device properties panel — directly in the editor, no external PDF reader needed.

Benefit: one file = one complete device. If you hand a machine over as a tarball, the full manufacturer info is included.

Diagnostic bits — structured, decodable

Vendor devices list their bits in the FDD’s <DiagnosticDecode> block:

<DiagnosticDecode bitOffset="3" length="1">
  <Description lang="DE">Drahtbruch Kanal 3</Description>
  <Description lang="EN">Wire break channel 3</Description>
  <Severity>warning</Severity>
</DiagnosticDecode>

Studio parses these blocks and shows them in the properties panel under the diagnostics tab — with live value per bit from the running PLC. You see immediately which bits are active and what they mean, in German or English.

Via the MCP catalog.diag_bits it is also accessible to the AI assistant — AI diagnostic loops can then answer concretely:

“Module Stachelbeere reports wire break on channel 3 (severity warning, active since 14:32:05). Check the wiring to terminal X3.”

Module picker with protocol filter

For modular bus couplers (e.g. Weidmueller UR20 with ProfiNet IRT coupler + a colourful module selection) every coupler has a <ModuleProtocol> entry in its FDD that says which module families it understands. Studio uses this for a filtered module picker:

  • You select the coupler
  • Studio shows only the modules that are compatible with this coupler
  • No 200-entry list to guess from by hand
  • No accidental selection of an incompatible module

Background: commit 5fe1e69. Spec reference: bus-system-v1.md §7.

FDD editor in Studio

In addition to the read path, there is also an FDD editor for the case that a manufacturer FDD is incomplete or you have to register your own component:

  • Diagnostics tab — edit <DiagnosticDecode> in a structured way, bit offset + description + severity
  • Documents tab — drop in a PDF, it becomes CDATA-embedded in the <Document> section
  • Geometry persist — window positions + zoom levels are remembered per file

Source commit: 6774397 (diagnostics + documents tabs).

Catalog performance — from 30 s to sub-second

Initially the catalog auto-import at Studio startup re-parsed every FDD with its embedded PDF — cold start took 30+ seconds with a medium catalog.

Fix in commit 3ee7cd6: no BLOB read in auto-import; the PDF is loaded lazily on click on the device. Cold start: sub-second.

Licence + distribution

ForgeIEC ships with a built-in Weidmueller catalog (commit 66923df):

  • 100+ modules complete with data sheet + diagnostics
  • Git-LFS-managed — catalog/ directory in the source tree
  • All licence notices embedded in the <Vendor> tags of the FDDs

Other manufacturers will follow. Custom FDDs can be imported via File → Import FDD — when the manufacturer does not publish PLCopen FDD itself, you can convert GSDML/EDS/ESI into the ForgeIEC format via the FDD editor.

What the commits delivered

  • 66923df — Weidmueller FDDs with CDATA-embedded PDFs + Git-LFS
  • 5dc087c — FDD-driven diagnostic-bit resolver + diagnostics tab
  • 5fe1e69 — <ModuleProtocol>-based module-picker filter
  • 6774397 — FDD editor with diagnostics + documents tabs
  • 3ee7cd6 — cold-start performance: no BLOB read in auto-import
  • aea0d4f — spec docs of the <DiagnosticDecode> section

Spec: documentation/architecture/bus-system-v1.md §7 (manufacturer data lifecycle).

Where you use it

You want …How
Look at the data sheet of a moduleClick in the bus tab, documents tab
Understand diagnostic bits of an active deviceDiagnostics tab with live values
Maintain a missing FDD yourselfFile → New FDD, editor tabs
AI diagnostics with plain-text answerscatalog.diag_bits MCP tool
Hand the machine over as a tarballFDDs + data sheets are inside the project

Where to read more