Calibration Terms

Calibration Terms: Sensor, Transducer, and Transmitter


Calibration is a mandatory component of measurement. For example, a weighing scale’s reliability becomes questionable without accurate measurement. Likewise, the most seemingly insignificant variances in a vernier calliper distort its correctness and, therefore, its efficiency as a measurement tool. Calibration is, therefore, essential for metrics such as pressure, especially in manufacturing equipment.

Pressure calibration compares a pressure-measuring device’s output with the pressure measurement standard or another similar device. Calibration systems incorporate varying instruments, including sensors, transducers, and transmitters. The most efficient testing and calibration laboratories will combine this equipment based on the device under measurement. Regardless, understanding which tool is best for what circumstance begins with understanding the tools themselves.

  1. Sensors

A sensor is fundamental in pressure calibration. A sensor receives signals from its surrounding environment and reacts to them. It is a device directly affected by a body or phenomenon bearing a weight requiring measurement. A signal is a form of energy like chemical reaction, heat, light, and motion. Therefore, the sensor is triggered by the physical environment and responds depending on the variable under measurement.

  1. Transducers

A transducer provides an output quantity with specific relation to the input quantity. It generates a signal proportional to the pressure applied to the sensor. Simply put, a transducer converts one type of energy into another, such as input pressure into electrical output.

Moreover, the transducer takes the analogue signal from the sensor and translates it into reading with multiple possible outputs like digital, current, or voltage. As a result, pressure transducer reading display is often in different units such as bar, psi, and Pa.

Distinguishing sensors and transducers

Sensors and transducers are easily indistinguishable. However, all sensors are transducers, but not all transducers are sensors. The difference lies in the types of transducers:

Input transducers

An input transducer takes any form of energy and converts it into another form. This transducer combines sensor and signal conditioning circuits, hence the ambiguity between transducers and sensors.

To illustrate, a microphone is an input transducer that senses the soundwave and a diaphragm sensor converts the sound energy into electrical signals. Thermocouples directly convert thermal energy into electrical energy. The interaction with the physical environment makes it a temperature sensor. However, the thermocouple display cannot display temperature directly, and the output signal needs further processing.

Pressure sensors that convert pressure signals into electrical signals include variable capacitors, metal films, and strain gauges.

Output transducers

An output transducer does not take input from a physical variable. Rather, it converts input energy into the physical variable. For example, a heater converts electric energy into thermal energy, a physical quantity.

The output transducer does not detect environmental stimuli but transmits signals into the environment. This feature makes it distinguishable from a sensor, unlike the input transducer.

  1. Transmitters

Transducers and transmitters are often used interchangeably. However, a transmitter refers to a specific transducer that sends the pressure reading as a current. The output readings range from 4-20mA, or 1-4V relative to the pressure input.

Like a transducer, a transmitter picks raw data from the sensor and converts it into electric current. Electric current easily sends data over long distances, allowing the unit to transmit the readings remotely. The transmitter, therefore, facilitates convenient monitoring of pressure, temperature, and other data.Sensors, transducers, and transmitters are essential pressure gauge calibration equipment. They are crucial in the manufacturing industry, where conditions like pressure must be precise depending on the device. Remember that erroneous readings can be detrimental to efficient systems. Therefore, periodic calibration ensures that equipment remains reliable and guarantees optimal workflow.

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