Instrument index
By Saad, practising automation engineer · Updated 2026-09-25
A master list of every instrument tag on the project, usually with service, P&ID, and location.
The instrument index is the tag census: tag, description, service, P&ID, area, manufacturer, model, range. It is not the Loop Register (which also stores cables, terminals, and I/O addresses) and not the IO list (which is organised by signal for the DCS/PLC).
SchematicForge ships a free instrument-index Excel template. Generated loop documentation uses the Loop Register as the live file; keep the index if your client’s document list still requires one.
SchematicForge uses this term in generated loop diagrams, the Loop Register, and termination lists.