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Control and Instrumentation Glossary

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Highway Addresable Remote Transducer
Open protocol that supports two way digital communications for process measurement and control devices.
Further Reading


A widely used nickel-molybdenum-chromium alloy.
Offers excellent resistance to wet chlorine, hypochlorite bleach, ferric chloride and nitric acid.
Further Reading


High Integrity Protective System - or sometimes High Integrity Protection System
An automatic safety system with a SIL level of 3 or more
Further Reading
SIL Ratings Guide

Human Machine Interface
A dated term superseded by SCADA
Further Reading


Hot Work
This includes welding or the use of any flame or electric arc or the use of any equipment likely to cause heat or flame or spark.
Soldering is often regarded as hot work.
Further Reading


High Pressure
Often used with reference to a utility or vent line e.g. HP air supply
Further Reading


Hydraulic Power Unit

Further Reading
Hydraulic Cleanliness Guide

HSE - Health and Safety Executive
Authority responsible for the regulation of almost all the risks to health and safety arising from work activity in Britain.

Further Reading


An undesirable oscillation which continues for some time after an external stimulus has disappeared.

Further Reading


A pressure test of piping; pressure vessels or pressure-containing parts; usually performed by pressurising the internal volume with water.

Further Reading


The reading of the same value differs as a function of whether the measurement is rising or falling.
Also known as deadband.
Further Reading


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C&I Resources

Cable Gland Selector
CE Marking
Flange Dimensions
Ingress Protection
Pipe Schedules
Relief Valve Orifice Size
Temperature Class
Temperature Conversion
Thermocouple Types
Valve Leakage
Vortex Meters
Wires and Cables


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