ISA Instrumentation Codes used in Process Control Systems

A calculator tool for determining ISA instrumentation codes based on process variable and instrument type. Select a process variable and instrument type to generate the corresponding ISA code used in P&ID diagrams.

Calculator

Inputs

Process Variable

Instrument Type

Identification Number (Optional)

Results

ISA Instrumentation Code--

Process Variable	Symbol	Instrument Type	Symbol
Analyses	A	Alarm	A
Burner	B	Users Choice	B
Combustion	B	Controller	C
Users Choice	C	Control valve	CV
Users Choice	D	Trap	CV
Voltage	V	Sensor (primary element)	E
Flow Rate	F	Rupture disc	E
Users Choice	G	Sight or gage glass	G
Current (electric)	I	Monitor	G
Power	J	Indicator	I
Time	K	Control Station	K
Level	L	Light (pilot/operation)	L
Users Choice	M	Users Choice	N
Users Choice	N	Flow Resistance Orifice	O
Users Choice	O	Test point (sample point)	P
Pressure / Vacuum	P	Recorder	R
Radiation	R	Switch	S
Speed (or Frequency)	S	Transmitter	T
Temperature	T	Multifunction	U
Multivariable	U	Valve/Damper	V
Vibration	V	Well	W
Weight (force)	W	Unclassified	X
Unclassified	X	Relay	Y
Event	Y	Driver	Z
Position, dimension	Z	Actuator	Z

Example

A level indicator will receive the symbol L for the process variable "Level", and I for the "Indicator" type of instrument.

Combined ISA Code: LI

For unique identification within a system, it is common to add a number to the ISA code. For example, the code for level indicator no. 8 would be: LI-8 or LI8