Instrumentation is the ability to control a process by measuring the value or the parameters set for the process. This can include control, flow, level, pressure and temperature.

Instrumentation & Controls standards

API Standards

• API RP 521 - Guides for Pressure Relief and Depression Systems
• API RP 550 - Manual on Instrumentation of Refinery Instruments and Control Systems
• API RP 551 - Process Measurement Instrumentation
• API RP 552 - Transmission Systems
• API RP 554 - Process Instruments and Controls
• API RP 598 - Valve Inspection and Testing

ISA Standards

• ISA 5 - Documentation of Measurement, and Control Instruments and Systems
• ISA 5.1 - Instrimentation Symbols and Identification
• ISA 12 - Electrical Equipment for Hazardous Locations
• ISA 18 - Instrument Signals and Alarms
• ISA 37 - Instrument Transducers
• ISA 50 - Signal Compatibility of Electrical Instruments
• ISA 60 - Control Centers
• ISA 75 - Control Valve Standards
• ISA 82 - Electrical and Electronic Instrumentation
• ISA 90 - Instrumentation and Computer Grounding
• ISA 91 - Criticality Ranking for Instrumentation
• ISA 99 - Industrial Automation and Control Systems Security
• ISA 100 - Wireless Systems for Automation
• ISA 101 - Human-Machine Interface
• ISA 104 - Device Integration
• ISA 106 - Process Automation for Continuous Process Operations
• ISA 107 - Advanced Measurement Techniques for Gas Turbine Engines
• ISA 108 - Intelligent Device Management

Instrumentation & Controls Glossary

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A

• Analog  -  A continuous electronic variable signal caring information.

• Analog Output  -  A signal coming from a PLC into an instrument or controller.

• Automatic Well Test  -  Specified as on instrument bubbles on Piping and Instrumentation Diagram.

B

C

• Car Seal  -  Specified on instrument bubbles on Piping and Instrumentation Diagram.

D

• Differential Pressure Flowmeter  -  There are many different types of instruments for measuring pressure.  The functions of these instruments are to monitor and control pressure in a process stream.

• Differential Set Pressure  -  The pressure difference between the set pressure and constant back pressure.

• Discrete Input  -  Relative to the device that reads either a TRUE or a FALSE, 1 or 0, or ON of OFF as an input signal.

E

F

• Flow Quality Indicating Transmitter  -  , abbreviated as FQIT, is an instrument that is used for measuring the amount of a liquid and a gas in two pase flow.

• Flow Switch  -  Provides a discrete input to the PLC.  The flow switch is typically used as a method of control in tanks, vessels, pumps and other types of process equipment.

• Flowmeter  -  An instrument used to measure the flow rate of gasses and liquids.

G

H

I

J

K

L

M

• Meter  -  A device that provides a measurement for the flow change in a gas or liquid.

N

O

• Orifice Area -

• Orifice Center of Head  -

• Orifice Discharge Coefficient  -  The ratio of actual discharge to the theoretical discharge.

• Orifice Flange  -  Meters the volumetric flow rate of liquids and gasses through a pipe.  Two orifice flanges are called an orifice flange union.

• Orifice Flow Rate  -  The amount of fluid that flows in a given time.

• Orifice Gravitational Constant  -

• Orifice Head Loss  -

• Orifice Plate  -  Measures the flow of a liquid or gas by the difference in pressure from the upstream to the downstream.

• Orifice Pressure Loss  -

• Orifices and Nozzles on a Horizontal Plane  -

• Orifices and Nozzles on a Vertical Plane  - 

P

• Position Switch  -  Provides a discrete input to the PLC.  The position switch is used to confirm the position of a critical component in the process, often a valve.

• Pressure Differential Transmitter  -  Measures the difference between a high pressure input and a low pressure input.  This can be used to measure process properties such as flow, density, level, viscosity and temperature.

• Pressure Indicating Transmitter  -, abbreviated as PT and PIT, is an instrument for measuring, controlling and indicating positive, negative or differential pressures of different fluids.

• Pressure Indicator  -  It is a field instrument that requires little to no maintenance.

• Pressure Switch  -  A discrete input to the PLC.  The pressure switch is typically used as a method of control in tanks, vessels and over all process control.

Q

R

• Resistance Temperature Detectors  -  A sensor used to measure temperature by correlating the resistance of the element with temperature.

S

T

• Temperature Controller  -  An instrument designed to minimize operator input or involvement.  A temperature controller has an input that is connected to a temperature source such as an RTD or other type of temperature element.

• Temperature Differential Switch  -  Contains the same functionality of a temperature switch with the exception that it is looking for the difference of temperature rather than a single input.

• Temperature Recorder  -  A device that records the temperature of a process.  This could be a data logger or a temperature transmitter capable of storing data.

• Temperature Switch  -  Provides alarm, shutdown and control for many types of processes.  Switch that activates when a certain temperature condition is met.

• Thermowell  -  Used in temperature measurement and provide isolation from the temperature sensor and the process fluid. 

U

V

• Velocity Flowmeter  -

W

X

Y

Z

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