Instrumentation can be defined as the application of instruments, in the form of systems or devices, to accomplish some specific objective in terms of measurement or control, or both. It is the branch of engineering that deals with measurement and control. Instrumentation is a device that measures or manipulates physical variables such as flow, temperature, level, or pressure etc.

Instrumentation components

  1. Measurements
  2. Controller or Automation




The measurement section measures the actual value of the desired element. The most important parameters that are measured in the industry for control:

  1. measurement of flow
  2. measurement of Level
  3. measurement of Pressure
  4. measurement of Temperature

Measurement features

  • Range
  • Zero measurement
  • Zero Drift
  • Sensitivity
  • Resolution
  • Response
  • Linearity
  • Hysteresis
  • Accuracy
  • Repeatability

Flow measuring equipment

To measure the flow or flow rate, there are different techniques, each of them is suitable for measuring the flow rate of a particular fluid. In this regard, it is worth mentioning that flow measuring equipment includes flow meter, flow switch and flow transmitter, which are described in the following:

  • Flow meter
  • Flow switch
  • Flow Transmitter


Flow meter:

A flow meter (or flow sensor) is an Instrumentation used to measure linear, nonlinear, mass or volumetric flow rate of a liquid or a gas.

Depending on the types of fluids there are different technologies used to measure the flow rate of these fluids.

  • Turbine Flow Meter
  • Differential Pressure Flow Meter (DP)
  • Magnetic Flow Meter
  • Mass Flow Meter (Coriolis)
  • Ultrasonic Flow Meter
  • Vortex Flow Meter
  • Rota meter
  • Orifice Plate flow meter
  • Venturi flow meter
  • Thermal mass flow meter

Flow switch:

Flow switches are responsible for controlling and monitoring the flow of liquids, air or other gaseous media through a system. If the rate exceeds or drops below what’s required, it can instantly trigger a series of actions such as activating an alarm, powering on a pump, diverting flow, shutting off parts of the system. Which actions a switch performs will depend entirely on the type of switch and what it’s been designed for.


Instrumentation  Types of flow switches

  • paddle flow switch
  • Piston flow switch
  • Ultrasonic flow switch
  • Thermal or heating flow switch
  • Linear flow switch
  • Turbine flow switch

Flow Transmitter

One of the principal requirementsin a Chemical Plant is the transmission of flow rates. Transmission may be required for flow (or some other parameter) control or to the supervisory control for data collection and monitoring. This objective is achieved by Flow Transmitters. Flow transmitters use positive displacement (PD), true mass flow, ultrasonic, electromagnetic and other measurement techniques.

Level measuring equipment

Level is one of the parameters that is important to measure and control in industrial processes. The purpose of Level measurement is to measure quantitatively the liquid content in tanks. Types of Level measuring equipment includes: level gauge or level meter, level switch, level transmitter. The following is a brief description of the types of level measuring equipment.

Level gauge or level meter

Level gauges are meters used to determine the level of a liquid in a fixed storage or process tank.  The gauge is composed of several parts including head, float, measuring tape, bottom anchored bracket, guide wires, elbows, anchors, coupling, pipe support brackets, and pipework. Liquid level gauge calibration is used to ensure proper readings are obtained when using level gauges.

 Types of level gauges

  • Reflex level gauges
  • Transparent level gauges
  • Bi-color level gauges
  • Magnetic level gauges


Instrumentation Level switch

A level switch can be described as a device that can sense the level of a liquid in a process tank. It is choosing where extreme low or high levels need to be measured and also used to control valves and pumps so that it can maintain the fluid level at a set value and also that it can prevent the tanks from overfilling. They are one of the most widely used sensors in the oil, gas, petroleum products, pharmaceutical and other industries.

Types of Level switch

  • Capacitance Level Switch
  • Conductive Level Switch
  • Diaphragm Level Switch
  • Displacer Level Switch
  • Float Level Switch
  • Optical Level Switch
  • Paddle Level Switch
  • Vibration Level Switch

Level transmitter

  • A level transmitter is perfect for a condition where the exact level of fluid needs to be measured. Level transmitters provide continuous level measurement over the range of the system rather than at a single point and produce an output signal that directly correlates to the level within a vessel. From depth and pressure, to float, radar, ultrasonic, and capacitive, these transmitters employ different technologies designed individually for specific level applications. Level transmitters include several types, each with a different structure and function. Types of Level transmitter
  • Hydrostatic
  • Ultrasonic
  • Radar
  • Capacitance
  • Magnetic
  • Liquid
  • Displacer

Pressure measuring equipment

The pressure obtained by dividing the unit of force by the unit of level is one of the most important quantities that is widely used in industry and is measured. There are many ways to measure pressure and vacuum.

Methods of pressure measurement:

  • Absolute pressure: Absolute pressure is the pressure quantity measured relative to zero which in pressure terms is a perfect vacuum
  • Measuring pressure: It is a pressure that is measured based on atmospheric pressure and is considered as a reference or zero reference.
  • Differential pressure or pressure difference: is the pressure difference between two distinct points of a system.

Types of pressure measuring equipment:

  • Pressure gauges
  • Pressure transmitter
  • Pressure switches

pressure gauge is a device which

  1. Measurement of fluid pressure in gas and liquid transmission pipes
  2. Measurement of gas and air pressure in the combustion lines of industrial furnaces
  3. Measuring gas pressure on pressurized tanks

Common Types of Pressure Gauges

Analog pressure gauge

The analog pressure gauge is a traditional type of pressure gauge. They use needles and mechanical internals to function. Accurate and reliable analog gauges are highly adaptable and can be used in many different applications.

Digital pressure gauge

Electronic or digital pressure gauges are modern equipment. They usually have diaphragms and strain gauges. They are characterized by their digital display, this kind of small air pressure gauge makes readings easier to identify and record.

Differential pressure gauge

Differential pressure is a measure of one pressure relative to another. Therefore, the differential pressure gauge works by using two ports and measuring the pressure difference between the two ports. This kind of device that measures air pressure can be positive pressure or negative pressure.

Absolute pressure gauge

Absolute pressure gauges are designed to measure pressure relative to vacuum. This means that it will take readings under complete or absolute vacuum. As a result, the absolute pressure is always positive. Such an Instrumentation for measuring air pressure is mainly used for barometers, altimeters and atmospheric or deep vacuum equipment.

Hydraulic pressure gauge

The hydraulic pressure gauge provides a higher pressure range. For some models, it may be as high as several hundred bars. The hydraulic gauge should be used with oil.

Transmitters and pressure sensors:

Pressure transmitter is a device for measuring and controlling pressure. It converts the mechanical pressure into analog electrical signals and it is based on capturing the changes in voltage.

Pressure transmitters include the following:

  1. Standard pressure transmitters: they are compact, universal devices designed for almost all industrial applications and have a main purpose of measuring pressure range.
  2. Hydrostatic pressure transmitters: often called level transmitters because of their working principle and ability to measure level. Hydrostatic pressure transmitters work on the basis that the amount of pressure increases with depth. These devices are submersible and can be used for liquids and gases.
  3. Absolute pressure transmitters: used in cases when the pressure of gases or liquid is isolated from changes in atmospheric pressure. These pressure transmitters would be used when pressure that is being measured is not affected by any changes (such as temperature).
  4. Differential pressure transmitters: have two sensory diaphragms and can measure the difference between two pressures. Differential pressure transmitters will then produce an output signal with reference to a calibrated pressure range. These devices are very commonly used in monitoring various industrial processes.

Pressure switches

Pressure switches are used to make or break (open or close) electrical circuits at selected pressures to operate solenoid-operated valves or other devices used in the system. There are two main types of pressure switches

  1. Mechanical (electromechanical)
  2. Electronic (solid state)

Mechanical pressure switch

As its name implies, an electromechanical pressure switch measures pressure changes using mechanical means, such as with a diaphragm, a Bourdon tube, or a piston. The main advantages of mechanical pressure switches are their high reliability and the ability to operate without auxiliary power. In addition, they can typically handle higher voltages and amperages than electronic pressure switches.
Electronic Pressure Switches

This type of pressure switch is stable and has a long lifespan. Other advantages of electronic pressure switches are their flexibility. Switch point, output signal, delay time, hysteresis, and many other parameters can be individually adjusted to suit the application.

Temperature measurement equipment

Temperature is defined as the energy level of matter which can be evidenced by some change in that matter. Temperature measuring sensors come in a wide variety and have one thing in common: they all measure temperature by sensing some change in a physical characteristic.

These are some of the types of equipment used to control and measure

Instrumentation temperature:

  • Temperature sensors
  • Thermometers
  • Laser thermometer (infrared)
  • Bimetal thermometer
  • Thermostats
  • Temperature transmitter
  • Thermocouple
  • Temperature indicators
  • And ….

Control or Automations

Industrial automation systems are generally divided into four categories:

Control System enables the click here to operate in a way to give you the safest and optimum production. Nowadays, it is fully automatic. Once configured, it brings your whole plant over the screens of control room

  • Fixed automation systems
  • Programmable automation systems
  • Flexible automation systems
  • Integrated automation systems

Among the products used in industrial automation systems, the following can be mentioned:

  • PLC
  • HMI
  • Sensor
  • Relay
  • Encoder
  • Converters
  • Power supply
  • Limit Switch
  • Recorder or data logger
  • PLC:
    These controllers can automate a specific process, machine function, or even an entire production line. The PLC receives information from connected sensors or input devices, processes the data, and triggers outputs based on pre-programmed parameters.

Depending on the inputs and outputs, a PLC can monitor and record run-time data such as machine productivity or operating temperature, automatically start and stop processes, generate alarms if a machine malfunctions, and more. Programmable Logic Controllers are a flexible and robust control solution, adaptable to almost any application.

  • HMI:
    Human Machine Interface, often known by the acronym HMI, refers to a dashboard or screen used to control machinery. Line operators, managers and supervisors in industry rely on HMIs to translate complex data into useful information. For example, they use HMIs to monitor machinery to make sure it’s working properly. Easy-to-understand visual displays give meaning and context to near real-time information about tank levels, pressure and vibration measurements, motor and valve status and other variables.

Industrial Sensor

A Sensor is a device that identifies the progressions in electrical or physical or other quantities and in a way to deliver a yield as an affirmation of progress in the quantity. In simple terms, Industrial Automation Sensors are input devices which provide an output (signal) with respect to a specific physical quantity (input). In industrial automation, sensors play a vital part to make the products intellectual and exceptionally automatic. These permit one to detect, analyze, measure and process a variety of transformations like alteration in position, length, height, exterior and dislocation that occurs in the Industrial manufacture sites.

Instrumentation relay

The relay is actually a switch with electrical function. Many conventional relays use an electromagnetic coil to operate the switch, but there are other operating methods, such as SOLID STATE relays that have different operating principles. Industrial relays are used when a separate low-power signal must be used to control a circuit, or where multiple circuits with a single signal need to be controlled.

  • Encoder
    Encoder is a special type of sensor that receives position information and relays this information to other equipment. Encoders are used for position (POSITION), velocity (VELOCITY) and for motor shaft rotation (DIRECTION) and other moving mechanical equipment. They provide the information needed for precise speed control in applications such as ROTARY TABLE positioning, PICK AND PLACE, machine assembly, packaging, robotics, and more.

Communication converters

A device or equipment for converting standard or proprietary protocols to a suitable protocol for other devices or tools. Protocol is software that is installed on routers (ROUTER) to convert data formats, data rates, and protocols on the same network to browsing data network protocols.

Power supply

 It is a device that provides electrical energy for one or more uses. This device may be separate from the load or may be made as an integral device that attaches to its load. The power supply in its simplest form includes the input part and the output part of the power supply, which are mainly electrically isolated from each other. The most important parameters in the input and output of the power supply are as follows:

  • Input section includes input voltage, input ground, current consumption, surge current, input fuse, frequency, DC power supply, power error memory, PFC power factor correction
  • Output section includes output voltage, secondary ground, short circuit current, residual ripple or distortion, output characteristics, output current

Instrumentation LIMIT SWITCH

It is an electromechanical switch that has a mechanical actuator or actuator connected to the contacts and is used to detect the range of motion of objects in automated systems. When an object collides with its actuator, its contacts change position, causing the current to disconnect and reconnect.

Recorder or data logger (DATA LOGGER)

A data logger or recorder is an electronic device for storing output information from industrial measuring equipment (Instrumentation) over a specified period of time. This equipment has various types and applications that depending on the consumer application and the advice of the sales expert, a suitable model for the user is selected and suggested.

Types of data loggers

  • Portable information recorder
  • USB data loggers
  • Paper recorders
  • Graphic and graphic recorders.
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