ISA process instrumentation codes - and combinations.
It is common to make letter combinations in PI&D diagrams according ANSI/ISA S5.1-1984 (R 1992) "Instrumentation symbols and identification".
In addition to the letter combination a succeeding number as a unique identification of the actual instrument is commonly used. The numbering practice varies - some use a sequential number, others use a number related to the process line number or similar.
First Letter
First letter indicates a measured or initiating variable, or a modifier, such as Current (I), Speed (S) or Flow (F).
Measured or Initiating Variable
- A - Analysis
- B - Burner, combustion
- C - User's choice
- D - User's choice
- E - Voltage
- F - Flow rate
- G- User's choice
- H - Hand
- I - Current (electrical)
- J - Power
- K - Time, time schedule
- L - Level
- M- User's choice
- N- User's choice
- O- User's choice
- P - Pressure, vacuum
- Q - Quantity
- R - Radiation
- S - Speed, frequency
- T - Temperature
- U - Multivariable
- V - Vibration, mechanical analyses
- W - Weight, force
- X - Unclassified
- Y - Event, state or presence
- Z - Position, dimension
Modifier
- D - Differential
- F - Ration (fraction)
- J - Scan
- K - Time rate of change
- M - Momentary
- Q - Integrate, totalizer
- S - Safety
- X - X-axis
- Y - Y-axis
- Z - Z-axis
Second or Succeeding Letters
Second or succeeding letters indicates a readout or passive function, output function or a modifier function.
Readout or Passive Function
- A - Alarm
- B - User's choice
- E - Sensor (primary element)
- G- Glass, viewing device
- I - Indication
- L - Light
- N- User's choice
- O- Orifice, restriction
- P - Point (test connection)
- R - Record
- U - Multifunction
- W - Well
- X - Unclassified
Output Function
- B - User's choice
- C - Control
- K - Control Station
- N- User's choice
- S - Switch
- T - Transmit
- U - Multifunction
- V - Valve, damper, louver
- X - Unclassified
- Y - Relay, compute, convert
- Z - Driver, actuator
Modifier Function
- B - User's choice
- H - High
- L - Low
- M - Middle, intermediate
- N- User's choice
- U - Multifunction
- X - Unclassified
Examples - P&ID codes
Flowmeter - Indicating
- FI 001
Temperature - Transmitter
- TT 001
Control Valve
- FV 001
Position Switch - High Level
- ZSH 001
Related Topics
Measurements and Instrumentation
Measurement and instrumentation strategies.Process Control Systems
Instrumentation, design and documentation of process control systems.Process Control Systems Documentation
Documentation of process control systems - Block Flow Diagrams (BFD), Process Flow Diagrams (PFD), Piping and Instrumentation Diagrams (P&ID) and more.Temperature Measurements
Measurment of temperature - probes, sensors and transmitters.
Related Documents
BFD - Block Flow Diagram
A Block Flow Diagram is a schematic illustration of a major process.Comparing Flowmeters
A limited comparison of flowmeter principles - regarding service, rangeability, pressure loss, typical accuracy, upstream pipe diameters, viscosity and relative costs.CSI MasterFormat Specifications
Construction Specifications Institute's 2004 Master-Format Edition.Flowmeter - Accuracy
Introduction to accuracy in flow measurement devices.Greek Alphabet
The Greek alphabet is essential expressing formulas and in technical language.HVAC Diagram - Online Drawing Tool
Draw HVAC diagrams online with this Google Drive drawing tool.Instruments
Devices - sensors - communicating physical properties to observers.ISA Instrumentation Codes used in Process Control Systems
The ISA standards and symbols are important for the P&IDs and documents describing the process control system.Schematic illustration of a functional relationship between piping, instrumentation and system components.
Draw P&ID diagrams online in the browser with Google Docs.
Pipes and Equipment - Identification Labels
Tags and label colors used for mechanical, plumbing and piping systems.Proportional, integrating and derivative process controllers.
Signal Transmission - Standards
Standard signals used for transmission from sensor to controller.
Search
Search is the most efficient way to navigate the Engineering ToolBox.
- Popular internal searches in the Engineering ToolBox
Engineering ToolBox - SketchUp Extension - Online 3D modeling!
Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with older versions of the amazing SketchUp Make and the newer "up to date" SketchUp Pro. Add the Engineering ToolBox extension to your SketchUp Make/Pro from the Extension Warehouse!
Translate this Page
Translate this page to Your Own Language.
About the Engineering ToolBox!
Privacy Policy
We don't collect information from our users. More about
- the Engineering ToolBox Privacy Policy
We use a third-party to provide monetization technologies for our site. You can review their privacy and cookie policy here.
You can change your privacy settings by clicking the following button: .
Advertise in the ToolBox
If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. You can target the Engineering ToolBox by using AdWords Managed Placements.
Citation
This page can be cited as
- The Engineering ToolBox (2003). Process Instrumentation - ISA Codes. [online] Available at: https://www.engineeringtoolbox.com/isa-intrumentation-codes-d_415.html [Accessed Day Month Year].
Modify the access date according your visit.
