ISA-5.1 tag numbering check

By Saad, practising automation engineer · Updated 2026-09-25

Enter an instrument tag. The checker looks for one to four letters, an optional hyphen, a loop number, and an optional suffix letter. This is not an ISA-5.1 certificate. Plants use local schemes. SchematicForge uses the tag you supply on the IO list.

PT-1001 matches the pattern

  • Letters: PT
  • Measured variable: Pressure
  • Functions: Transmit
  • Loop number: 1001

Read the ISA-5.1 guide or run the IO list checker.