Build an I/O list.
From a P&ID set to a structured I/O list ready for PLC or DCS import
What this covers.
Building an I/O list is the engineering process of reading every instrument on a P&ID set, classifying each tag by signal class, AI, AO, DI, DO, and producing a structured spreadsheet keyed to loop number, source equipment, and P&ID page reference. The I/O list is the single document that drives PLC and DCS sizing, marshalling cabinet design, I/O module count, and the bid for the controls package. On a brownfield project the I/O list is built against a legacy drawing set. On a greenfield project it is rebuilt at every IFC revision. The I/O list is the foundation of the loop folder, the cable schedule, and the FAT package.
Inputs.
- P&ID set, PDF, scanned PDF, PNG, JPG, or TIFF
- Legacy I/O list, optional, for reconciliation
- House tag convention reference, optional
Outputs.
- Structured I/O list spreadsheet with one row per instrument tag
- Signal class classification, AI, AO, DI, DO, REVIEW
- Per-row loop number, source equipment, and P&ID page reference
- Reconciliation report against the legacy list, if uploaded
- Export targets. Excel, CSV, TIA Portal XML, Rockwell L5X, PLCCreator, JSON
Manual I/O list workflow vs. Extracted I/O list
| Step | Manual workflow | Tagsight workflow |
|---|---|---|
| Read the P&ID set | Page-by-page with highlighter | Upload the set, parsed in parallel |
| Classify signal class | ISA letter lookup per row | Auto-classified, REVIEW on uncertainty |
| Resolve loop number | Cross-reference per tag | Loop-consistency pass across pages |
| Handle non-ISA dialects | Custom rule set | 233 standards corpus reads as drawn |
| Reconcile with legacy list | Manual diff | Cross-document reconciliation |
| Export for PLC import | Hand-keyed into vendor tool | TIA Portal, Rockwell L5X, PLCCreator export |
Step by step.
- 01Upload the P&ID setDrop a PDF, PNG, JPG, or TIFF set into a Tagsight workspace. Scanned and CAD-exported PDFs both process. Multi-page drawings keep page-to-page off-page connector references intact.
- 02Pages process in parallelEach page runs through the extraction pipeline, per-page. Review can start on page 1 while later pages are still working.
- 03Review and confirmYou review and confirm every row in the canvas before export. Bubble overlays on the drawing canvas show the source location of every tag.
- 04Reconcile with legacyUpload an existing I/O list spreadsheet and the reconciliation view shows matched, new on drawing, missing from drawing, and disagreement buckets.
- 05Export to PLC vendor formatExcel, CSV, TIA Portal XML, Rockwell L5X, PLCCreator, JSON, and DEXPI export targets ship in the column shape each vendor expects.
Common questions
What if the P&ID uses a non-ISA tag convention, KKS, NEN, IEC 81346.
How long does a 100-page P&ID set take.
Can I separate SIS instruments from BPCS.
Related.
Start a workspace.
Upload the source documents, run the workflow, ship the document in the column shape the next consumer expects.