ISA Certified Control Systems Technician (CCST) Level 1 Study Guide Vocabulary

A comprehensive set of vocabulary terms and definitions derived from the CCST Level 1 Study Guide, covering certification requirements, calibration, loop checking, troubleshooting, and start-up domains.

Control Systems Technician (CST)

A professional skilled in pneumatic, mechanical, and electronic instrumentation who understands process control loops and systems, including computer-based ones.

Related Experience

Work performed in the instrumentation, measurement and control, electronics, electrical, and mechanical fields.

One (1) Year of Work Experience

Defined as $1500$ hours of active employment during a twelve ($12$) month period.

PDPs

Professional Development Points; $90$ points are required every three ($3$) years for CCST renewal.

Absolute Pressure Gage

A gage that would indicate atmospheric pressure (approximately $14.7\,psi$) when not connected to any process.

Hydrostatic Head

Another way of expressing pressure, often used in level measurement.

Specific Gravity

A dimensionless number calculated by dividing the density of the process fluid by the density of water or air.

Error

The difference between the indication of an instrument and the actual value of the measured variable.

Inferential Level Measurement

Methods of measuring level by using other physical properties, such as hydrostatic head, weight, or buoyancy.

Repeatability

The ability of an instrument to give the same indication each time it measures a variable under identical conditions.

Deadband

The range through which an input signal may be varied, upon reversal of direction, without an observable change in output.

Steady-state Gain

The ratio of the change in output to the change in input; for a $4-20\,mA$ transmitter over $200\text{ inches}$ of water, it is $\frac{16\,mA}{200\text{ inches}} = 0.08\,mA/\text{inch}$.

Thermocouple Red Lead

Under ANSI/ISA standards, the thermocouple or extension wire color that is always the negative lead.

Rectifier

A device that converts alternating current ($AC$) to direct current ($DC$).

Oscilloscope

A test instrument used to display a waveform.

Dead Weight Tester

A device used for the calibration of pressure gages up to high levels, such as $800\,psi$.

Line-of-Sight Location

An ISA-5.1 symbol indicator (such as a circle with no horizontal line) denoting an instrument is in a field-mounted location.

Reynolds Number

A dimensionless value used to determine if a fluid flow is laminar or turbulent.

$$C_v$$

The flow coefficient defined as the flow rate in gallons per minute of water ($SG = 1$) at a pressure drop of $1.0\,psi$ through a fully open valve.

Hysteresis

A type of error where the output of an instrument depends on the direction of the input change (increasing vs. decreasing).

Byte

A computer memory unit normally organized as an eight-bit segment of a computer word.

RAM

Random Access Memory; considered the most temporary form of information storage in a computer.

RTD

Resistance Temperature Detector.

Thermowell

A protective tube used to house temperature-sensing elements.

Lapping

The process of grinding the plug and seat of a valve together to ensure a tight seal and reduce leakage.

Impulse Lines

Piping or tubing used to connect process taps to pressure-sensing instruments.

Coriolis Effect

A physical principle associated with the operation of mass flowmeters.

Valve Trim

The internal parts of a control valve that come in contact with the process fluid, specifically the stem, plug, and seat ring.

Bubbler System

A level measurement system where air pressure in a purge pipe is equal to the pressure exerted by the liquid at the bottom of the tank.

Integral Action

A PID control mode, also known as reset, that eliminates offset.

Time Constant

In a transmission system, the time necessary (after dead time) for the response curve to reach $63.2\%$ of its final value following an upset.

Cavitation

A two-stage phenomenon where vapor bubbles form in a liquid and then suddenly collapse or implode back into a liquid state.

Laminar Flow

A flow regime characterized by smooth, parallel layers of fluid with no disruption between the layers.