Process Control Systems and Instrumentation
Expert-defined terms from the Professional Certificate in Industrial Automation and Control Systems course at London School of Planning and Management. Free to read, free to share, paired with a globally recognised certification pathway.
A/D Converter #
a device that converts analog signals to digital signals for processing and control, it is commonly used in process control systems to interface with sensors and actuators, the converter plays a crucial role in industrial automation and control systems, where it enables the use of digital control systems to monitor and control process variables, such as temperature, pressure, and flow rate, for example, in a chemical plant, an A/D converter can be used to convert the raw signal from a temperature sensor to a digital signal that can be processed by a control system.
Accuracy #
the degree of precision and exactness with which an instrument or system measures or controls a process variable, it is an important consideration in process control systems, where inaccurate measurements or control can result in poor product quality, reduced efficiency, and increased costs, for example, in a manufacturing plant, accurate control of a process variable, such as temperature, is critical to producing high-quality products.
Actuator #
a device that converts electrical or pneumatic energy into mechanical energy to perform a specific task, such as opening or closing a valve, it is commonly used in process control systems to control process variables, such as flow rate, pressure, and temperature, for example, in a power plant, an actuator can be used to control the position of a valve to regulate the flow of steam to a turbine.
Alarm #
a warning or notification that a process variable has exceeded a setpoint or has entered an alarm condition, it is an important feature in process control systems, where it enables operators to take corrective action to prevent equipment damage or product quality issues, for example, in a chemical plant, an alarm can be triggered when a process variable, such as temperature, exceeds a safe operating limit.
Analog Signal #
a continuous signal that represents a physical quantity, such as temperature, pressure, or flow rate, it is commonly used in process control systems to transmit information from sensors to control systems, for example, in a power plant, an analog signal can be used to transmit the temperature of a boiler to a control system.
Batch Processing #
a method of processing where a batch of material is processed in a sequence of steps, it is commonly used in process control systems, where it enables the production of high-quality products in a consistent and reliable manner, for example, in a pharmaceutical plant, batch processing can be used to produce a batch of medication that meets strict quality and safety standards.
Calibration #
the process of adjusting an instrument or system to ensure that it is accurate and reliable, it is an important consideration in process control systems, where inaccurate measurements or control can result in poor product quality, reduced efficiency, and increased costs, for example, in a manufacturing plant, calibration of a temperature sensor is critical to ensuring that the process variable is controlled within a narrow range.
Communication Protocol #
a set of rules and procedures that govern the exchange of information between devices or systems, it is commonly used in process control systems, where it enables the integration of devices and systems from different manufacturers, for example, in a power plant, a communication protocol, such as Modbus, can be used to enable the exchange of information between devices from different manufacturers.
Control Loop #
a feedback loop that consists of a sensor, a controller, and an actuator, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, a control loop can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Control System #
a system that uses algorithms and models to control a process variable, such as temperature, pressure, or flow rate, it is commonly used in process control systems, where it enables the control of a process variable to achieve a specific objective, for example, in a power plant, a control system can be used to control the speed of a turbine to generate electricity at a specific frequency.
Controller #
a device that uses algorithms and models to control a process variable, such as temperature, pressure, or flow rate, it is commonly used in process control systems, where it enables the control of a process variable to achieve a specific objective, for example, in a chemical plant, a controller can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
DAC #
a device that converts digital signals to analog signals for control and processing, it is commonly used in process control systems to interface with actuators and sensors, the converter plays a crucial role in industrial automation and control systems, where it enables the use of digital control systems to monitor and control process variables.
Data Acquisition #
the process of collecting and processing data from sensors and instruments to monitor and control a process, it is commonly used in process control systems, where it enables the monitoring and control of process variables, such as temperature, pressure, and flow rate, for example, in a power plant, data acquisition can be used to collect data from sensors and instruments to monitor the performance of a turbine.
DCS #
a type of control system that uses distributed control and modular architecture to control a process, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, a DCS can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Digital Signal #
a discrete signal that represents a physical quantity, such as temperature, pressure, or flow rate, it is commonly used in process control systems to transmit information from sensors to control systems, for example, in a power plant, a digital signal can be used to transmit the status of a valve to a control system.
Distributed Control System #
a type of control system that uses distributed control and modular architecture to control a process, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, a distributed control system can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Field Instrument #
a device that measures a process variable, such as temperature, pressure, or flow rate, it is commonly used in process control systems, where it enables the monitoring and control of process variables, for example, in a power plant, a field instrument can be used to measure the temperature of a boiler to ensure that it is operating within a safe range.
Feedback Control #
a type of control that uses feedback from a process to adjust the control action, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, feedback control can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Flow Rate #
the rate at which a fluid flows through a pipe or channel, it is commonly used in process control systems, where it enables the control of a process variable, such as flow rate, to achieve a specific objective, for example, in a power plant, flow rate can be used to control the speed of a turbine to generate electricity at a specific frequency.
HMI #
a device that provides a user interface to a control system, it is commonly used in process control systems, where it enables operators to monitor and control a process, for example, in a chemical plant, an HMI can be used to provide operators with a user interface to monitor and control the temperature of a reactor.
Instrument #
a device that measures a process variable, such as temperature, pressure, or flow rate, it is commonly used in process control systems, where it enables the monitoring and control of process variables, for example, in a power plant, an instrument can be used to measure the temperature of a boiler to ensure that it is operating within a safe range.
Loop Tuning #
the process of adjusting the parameters of a control loop to achieve optimal performance, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, loop tuning can be used to adjust the parameters of a control loop to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Modular Architecture #
a type of architecture that uses modular components to build a system, it is commonly used in process control systems, where it enables the flexibility and scalability of a system, for example, in a chemical plant, a modular architecture can be used to build a control system that can be easily expanded or modified as needed.
Network #
a system of connected devices that communicate with each other, it is commonly used in process control systems, where it enables the exchange of information between devices and systems, for example, in a power plant, a network can be used to enable the exchange of information between devices and systems to monitor and control the performance of a turbine.
Open #
Loop Control - a type of control that does not use feedback from a process to adjust the control action, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, open-loop control can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
PLC #
a type of controller that uses a programmable logic to control a process, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, a PLC can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Process Control #
the use of control systems to monitor and control a process, such as a chemical reaction or a physical process, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a power plant, process control can be used to control the speed of a turbine to generate electricity at a specific frequency.
Process Variable #
a variable that is measured and controlled in a process, such as temperature, pressure, or flow rate, it is commonly used in process control systems, where it enables the monitoring and control of a process, for example, in a chemical plant, a process variable, such as temperature, can be used to control the chemical reaction to ensure that it occurs within a narrow range.
Real #
Time Control - a type of control that uses real-time data to control a process, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a power plant, real-time control can be used to control the speed of a turbine to generate electricity at a specific frequency.
Relay #
a device that uses an electromagnet to control a circuit, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, a relay can be used to control the flow of a fluid to a reactor.
SCADA #
a type of system that uses supervisory control and data acquisition to monitor and control a process, it is commonly used in process control systems, where it enables the monitoring and control of a process, for example, in a power plant, a SCADA system can be used to monitor and control the performance of a turbine.
Sensor #
a device that measures a process variable, such as temperature, pressure, or flow rate, it is commonly used in process control systems, where it enables the monitoring and control of a process, for example, in a chemical plant, a sensor can be used to measure the temperature of a reactor to ensure that it is operating within a safe range.
Setpoint #
a value that is used as a target for a process variable, it is commonly used in process control systems, where it enables the control of a process variable, such as temperature, pressure, or flow rate, for example, in a chemical plant, a setpoint can be used to control the temperature of a reactor to ensure that the chemical reaction occurs within a narrow range.
Transducer #
a device that converts a physical quantity into an electrical signal, it is commonly used in process control systems, where it enables the monitoring and control of a process, for example, in a power plant, a transducer can be used to convert the pressure of a fluid into an electrical signal that can be used to control the flow of the fluid.
Valve #
a device that controls the flow of a fluid through a pipe or channel, it is commonly used in process control systems, where it enables the control of a process variable, such as flow rate, to achieve a specific objective, for example, in a chemical plant, a valve can be used to control the flow of a fluid to a reactor to ensure that the chemical reaction occurs within a narrow range.
Variable Speed Drive #
a device that controls the speed of a motor or pump, it is commonly used in process control systems, where it enables the control of a process variable, such as flow rate, to achieve a specific objective, for example, in a power plant, a variable speed drive can be used to control the speed of a turbine to generate electricity at a specific frequency.
VFD #
a type of drive that uses a variable frequency to control the speed of a motor or pump, it is commonly used in process control systems, where it enables the control of a process variable, such as flow rate, to achieve a specific objective, for example, in a chemical plant, a VFD can be used to control the speed of a pump to regulate the flow of a fluid to a reactor.