Industrial Instrumentation: Types, Applications and Selection Guide Industrial instrumentation refers to the instruments and systems employed to measure, transmit, display and control the process conditions within an industrial facility. Typical conditions are pressure, temperature, flow and level. The resulting measurements help operators and control systems monitor performance, maintain product quality and identify abnormal operating conditions. Quick definition: What is industrial instrumentation? Sensors, gauges, transmitters, analyzers, and other controls used to measure physical process variables. They can be either displayed locally or sent to a PLC, DCS or SCADA system or monitoring and control. Need help sourcing an industrial instrument? Send us the measurement variable, operating range, process conditions, connection and required output signal. Request a Quote What Is Industrial Instrumentation? An industrial instrument detects a process condition and converts it into useful information. A pressure gauge may provide a local reading, while a pressure transmitter can send an electrical signal to a control system. Together, these devices form industrial instrumentation systems that allow a process to be observed and adjusted. The terms sensor, transducer and transmitter are related but not identical. A sensor detects a physical variable. A transducer converts one form of energy into another, while a transmitter converts a measurement into a standard output, such as 4–20 mA. Smart transmitters may also provide digital configuration and diagnostic information through protocols such as HART. Main Types of Industrial Instrumentation The four core measurement variables are pressure, temperature, flow and level. Understanding these types of industrial instrumentation provides a useful starting point for selecting suitable measurement technology. Process variable Typical instruments Example application Pressure Gauges and pressure transmitters Monitoring a vessel, pipeline or pump Temperature RTDs, thermocouples and transmitters Measuring a reactor or heat exchanger Flow Coriolis, magnetic, vortex and ultrasonic flowmeters Measuring liquid, steam or gas flow Level Radar, ultrasonic and differential-pressure instruments Monitoring material in a tank or vessel Pressure instruments range from mechanical gauges, such as this WIKA direct-assembly pressure gauge , to electronic devices available through the pressure transmitters category . Selection depends on the required range, accuracy, process medium, connection and environmental conditions. How Does a Measurement and Control Loop Work? In a typical loop, a sensor detects a process variable. A transmitter then converts the reading into a usable signal and sends it to a PLC or DCS. The controller compares the measurement with a target value and may command a final control element, such as a control valve, to adjust the process. This relationship between measurement and automation is commonly called instrumentation and control. SCADA software may provide wider monitoring, alarms, trends and operator displays. A Piping and Instrumentation Diagram, or P&ID, documents instruments, control functions, pipelines and equipment using standard symbols and identification tags. Signal and mechanical connections must also be considered. For example, an instrumentation quick-connect stem with valve is a connection component rather than a measuring instrument, but it may form part of a wider installation. Where Is Industrial Instrumentation Used? Oil and gas, chemical processing, water treatment, power generation, manufacturing, food production and pharmaceutical facilities are areas of process instrumentation application. Typical applications include monitoring pipeline pressure, tank level, chemical dosing flow, heat-exchanger temperature and water conductivity. In practical terms, industrial instrumentation for process control gives operators and automation systems reliable information about current conditions. However, measurement quality depends on proper instrument selection, installation, configuration and calibration. How to Select Industrial Instrumentation Learning how to select industrial instruments requires more than choosing a device that measures the right variable. Engineers and buyers should define the complete operating and installation requirements before requesting a quotation. Process variable: Pressure, temperature, flow, level or analysis. Measurement range: Normal, minimum and maximum operating values. Performance: Required accuracy, repeatability and response time. Process conditions: Medium, pressure, temperature and density. Materials: Compatibility of wetted parts with the process medium. Installation: Process connection, mounting and available space. Output: 4–20 mA, HART or another required communication method. Environment: Ingress protection and hazardous-area requirements. Potential product options include a listed three-wire temperature or…