Instrumentation Components and Definitions

An operation that uses energy to produce a change in a material, or an energy conversion.

May be a quantity of energy or material which is to be adjusted to a definite value. Examples are pressure, level, flow, temperature and composition.

Is the desired value of the process variable

Referred to as deviation, is the difference between the actual value of the controlled variable and the set point.

Refers to the device that measures the value of a controlled variable. Are used to convert a measurement, such as pressure, temperature or flow, to a movement or signal that can be used for transmission to a controller, recorder or indicator

May take the form of changing flow rate, a variation in temperature or pressure or a number of other factors, that cannot be predicted.

The variable which is adjusted to bring the process variable back to the desired value or set point. In most cases, the manipulated variable is some form of flow.

The sensing element will be located at the process measurement site, and its output will be converted to a longer range signal by a ______________.

Instantly show the values of different variables to the operators and maintenance personnel. thermometers and pressure gauges are ones

Consist of one or more pen mechanisms, whose instantaneous position indicates the value of the variable (pressure, temperature, level or fl ow) being monitored or recorded on a chart for future reference.

It is the instrument that responds to the value of the process variable and positions the final control
element. It continuously compares the value of the process variable (usually a transmitter output signal) with
the set point.

The component of a control system that adjusts the value of the manipulated variable