First Letter Succeeding Letters Measured or Initiating Variable Modifier Readout or Passive Function Output Function Modifier A Analysis Alarm B Burner, Combustion User’s Choice User’s Choice User’s Choice C User’s Choice Control D User’s Choice Differential E Voltage Sensory (Primary) F Flow Rate Ratio (fraction) G User’s Choice Glass, Viewing H Hand High I Current Indicate J Power Scan K Time,
Time ScheduleTime Rate of Change Control Station L Level Light Low M User’s Choice Momentary Middle N User’s Choice User’s Choice User’s Choice User’s Choice O User’s Choice Orifice P Pressure, Vacuum Point, Test Q Quantity Integrate, Totalize R Radiation Record S Speed, Frequency Safety Switch T Temperature Transmit U Multivariable Multifunction Multifunction Multifunction V Vibration W Weight, Force Well X Unclassified x-axis Unclassified Unclassified Unclassified Y Event, State y-axis Relay, Compute Z Position, Dimension z-axis Driver, Actuator
(Adapted from Bruce G. Lovelace, "Piping and Instrument Diagrams", handout given at seminar held at Michigan Technological University, Dept. of Chemical Engineering, November 5, 1992)
This page is maintained by Tomas B. Co (tbco@mtu.edu). Last revised 12/2/1999.
Tomas B. Co
Associate Professor
Department of Chemical Engineering
Michigan Technological University
1400 Townsend Avenue
Houghton, MI 49931-1295