Instrument Loop Test

The below points need to be tested during a instrument loop test.


Check the below points for the instruments in the field.

  • Air Isolation correct
  • Accessible
  • Location correct per Loop diagram and P&ID
  • Input continuity check
  • Calibration
  • Range check with Control system
  • Loop direct/reverse action
  • Serial number correct
  • State change OK on control system


  • Fuse/breaker lock box available
  • Accessibility of terminations
  • Lighting suitable
  • Starters and push buttons
  • Cabinet air fan acceptable?
  • Labels on cabinet door correct
  • Wires labeled
  • Cables labelled


  • DCS/PLC panels labelled
  • Termination panel access suitable
  • Termination drawing suitable
  • Fuse in place


  • Interlock data on loop and P&ID correct
  • All loop diagram data correct
  • Master copy red lines for final mark up
  • Control room has copy until as built issued


Instrument Loop Test.pdf (35.4 KB)