Catalog of Electrical Engineering questions with useful answers that help you develop a clear insight of your conceptual problems.
List of topics:
A device converting one standardized instrumentation signal into another standardized instrumentation signal, and/or performing some sort of processing on that signal. Often referred to as a converter and sometimes as a “relay.” Examples: I/P converter (converts 4- 20 mA electric signal into 3-15 PSI pneumatic signal), P/I converter (converts 3-15 PSI pneumatic signal into 4-20 … Read more
The physical system we are attempting to control or measure. Examples: water filtration system, molten metal casting system, steam boiler, oil refinery unit, power generation unit. Similar Basic Questions in Industrial and Control Systems Engineering: Reference and Further Reading: Basics of Industrial Instrumentation Handbook
Lower- and Upper Range values abbreviated LRV and URV, respectively are the values of process measurement deemed to be 0% and 100% of a transmitter’s calibrated range. For example, if a temperature transmitter is calibrated to measure a range of temperature starting at 300 degrees Celsius and ending at 500 degrees Celsius, its LRV would … Read more
A device translating the signal produced by a primary sensing element (PSE) into a standardized instrumentation signal such as 3-15 PSI air pressure, 4-20 mA DC electric current, Fieldbus digital signal packet, etc., which may then be conveyed to an indicating device, a controlling device, or both. Similar Basic Questions in Industrial and Control Systems … Read more
A device directly sensing the process variable and translating that sensed quantity into an analog representation (electrical voltage, current, resistance; mechanical force, motion, etc.). Examples: thermocouple, thermistor, bourdon tube, microphone, potentiometer, electrochemical cel l, accelerometer. Similar Basic Questions in Industrial and Control Systems Engineering: Reference and Further Reading: Basics of Industrial Instrumentation Handbook
The value at which we desire the process variable to be maintained at. In other words, the “target” value for the process variable. Similar Basic Questions in Industrial and Control Systems Engineering: Reference and Further Reading: Basics of Industrial Instrumentation Handbook
The specific quantity we are measuring in a process. Examples: pressure, level, temperature, flow, electrical conductivity, pH, position, speed, vibration. Similar Basic Questions in Industrial and Control Systems Engineering: Reference and Further Reading: Basics of Industrial Instrumentation Handbook
Zero and Span are alternative descriptions to LRV and URV for the 0% and 100% points of an instrument’s calibrated range. “Zero” refers to the beginning-point of an instrument’s range (equivalent to LRV), while “span” refers to the width of its range (URV − LRV). For example, if a temperature transmitter is calibrated to measure … Read more
A device receiving a process variable (PV) signal from a primary sensing element (PSE) or transmitter, comparing that signal to the desired value (called the setpoint) for that process variable, and calculating an appropriate output signal value to be sent to a final control element (FCE) such as an electric motor or control valve. Similar … Read more
The quantity in a process we adjust or otherwise manipulate in order to influence the process variable (PV). Also used to describe the output signal generated by a controller; i.e. the signal commanding (“manipulating”) the final control element to influence the process. Similar Basic Questions in Industrial and Control Systems Engineering: Reference and Further Reading: … Read more