Build an I/O list.
From a P&ID set to a structured I/O list ready for PLC or DCS import
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
| 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.
- 01
Upload the P&ID set
Drop 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.
- 02
Pages process in parallel
Each page runs through the extraction pipeline (per-page). Review can start on page 1 while later pages are still working.
- 03
Review and confirm
Each row is auto-accepted above the confidence threshold or flagged for review. Bubble overlays on the drawing canvas show the source location of every extracted tag.
- 04
Reconcile with legacy
Upload an existing I/O list spreadsheet and the reconciliation view shows matched, new on drawing, missing from drawing, and disagreement buckets.
- 05
Export to PLC vendor format
Excel, 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)?
Yes. The standards corpus covers 233 dialects including ISA 5.1, KKS, IEC 81346, NEN Dutch HVAC, DIN 19227, NORSOK, JIS, GOST, and in-house conventions. Tags read as drawn; the dialect detector votes on the active standard from the page evidence.
How long does a 100-page P&ID set take?
Pages process in parallel. Review begins on the first pages while later pages are still working. A 100-page set is typically reviewable within an hour of upload; the bulk of the human time is review, not extraction.
Can I separate SIS instruments from BPCS?
Yes. Signal class plus SIS tag prefix (PSH, PSL, PALL, PAH, PSV, ZSO, ZSC, XV) separates regulatory loops from protective ones. The SIS subset exports to a dedicated workbook sheet for IEC 61511 evidence.
Start a workspace.
Upload the source documents, run the workflow, ship the document in the column shape the next consumer expects.