The most frequently used test bench sensors
On a test bench, sensors are used to measure the physical parameters needed to analyze the behavior of a product under test. Depending on the type of test, they can measure force, pressure, displacement, velocity, temperature, humidity, or light intensity.
These measurements are then used to control the test, verify product compliance, detect anomalies, or compare multiple results. A sensor that is poorly selected, improperly positioned, or incorrectly calibrated can skew the interpretation of the data, even if the test bench is properly designed.
The most commonly used sensors on a test bench are generally force sensors, pressure sensors, position sensors, speed sensors, optical sensors, and humidity sensors. The choice of sensors depends on the product being tested, the required accuracy, the test environment, and the type of data to be analyzed.
SOMMAIRE
What are the sensors on a test bench used for?
A sensor converts a physical quantity into measurable data. On a test bench, it is used to monitor what is happening during the test: applied force, pressure in a circuit, component displacement, rotational speed, temperature, humidity, or the presence of a light signal.
This information is used to control the test, compare results, and verify whether the product being tested meets the expected criteria. For example, a pressure sensor can monitor the performance of a hydraulic system, while a force sensor can measure tensile, compressive, or bending forces.
The choice of sensor therefore depends on the type of test being performed, the required accuracy, and the environment in which the test bench operates. A sensor used on a hydraulic test bench does not always have to meet the same requirements as a sensor integrated into a mechanical test bench.
What types of sensors are used on a test bench?
Depending on the type of test being performed, a test bench may incorporate several sensors to measure the physical parameters required for product analysis. The table below lists the most common types of test benches and their primary uses.
Type de capteur | Mesure réalisée | Exemple d’utilisation sur banc d’essai |
Capteur de force | Effort, traction, compression, flexion | Mesurer la résistance d’une pièce, d’un matériau ou d’un assemblage |
Capteur de pression | Pression hydraulique ou pneumatique | Suivre un essai d’étanchéité, une épreuve hydraulique ou une pression cyclée |
Capteur de déplacement | Course, position, déformation | Contrôler la position d’un vérin ou mesurer la déformation d’un produit |
Capteur de vitesse | Vitesse de rotation ou de déplacement | Suivre un moteur, un axe, un actionneur ou un cycle dynamique |
Capteur optique | Présence, distance, position, contraste | Détecter une pièce, contrôler un repère ou mesurer sans contact |
Capteur d’humidité | Humidité ambiante ou environnementale | Suivre les conditions d’un essai climatique, d’endurance ou de vieillissement |
Force and pressure sensors
Force and pressure sensors are among the most common types of sensors found on a test bench. They are used to measure the forces applied to a product or the pressure within a hydraulic, pneumatic, or mechanical system.
These measurements are useful for verifying a component’s strength, monitoring pressure changes, tracking a test cycle, or detecting abnormal behavior during testing.
The force sensor
The force sensor measures forces applied in tension, compression, bending, or shear, depending on the configuration used. It is commonly found on mechanical test benches, particularly for characterizing the strength of a part, material, or assembly.
On a test bench, for example, it can be used to measure the force required to deform a product, verify its mechanical strength, or monitor changes in force during a repeated cycle.
The hydraulic pressure transducer
The hydraulic pressure transducer measures the pressure of a fluid in a circuit. It is used on hydraulic test benches to monitor pressure during a leak test, a hydraulic test, a performance test, or a pressure cycling test.
This type of sensor should be selected based on the pressure range to be measured, the required accuracy, the nature of the fluid, and the required sampling rate during the test.
The force or torque sensor
Some tests also require measuring operating force or torque. This is the case, for example, when a test bench needs to verify the behavior of a valve, a tap, a shaft, or a mechanism subjected to repeated stresses.
These measurements provide a better understanding of the product’s wear, its operational consistency, or the development of a mechanical seizure during the test.
Position and motion sensors
Position and motion sensors are used to track the movement of a component during a test. They are used when it is necessary to measure stroke, angular position, distance change, or the movement of an actuator.
On a test bench, these measurements are useful for monitoring the position of a cylinder, tracking the deformation of a product, verifying the movement of a mechanism, or synchronizing multiple movements during an automated cycle.
Incremental and absolute encoders
Encoders are used to measure position or rotation. An incremental encoder indicates changes in position relative to a reference point, while an absolute encoder provides a known position directly, even after a power outage.
They are often used on motorized axes, actuators, or rotary systems to precisely track movement or rotation during testing.
LVDT linear displacement sensors
The LVDT sensor measures linear displacement with high accuracy. It is suitable for tests in which you need to monitor the stroke, deformation, or position of a component over time.
It is used, for example, on mechanical test benches to measure the displacement of a part under load, or on hydraulic test benches to monitor the stroke of a cylinder.
Inductive and capacitive proximity sensors
Proximity sensors can detect the presence or absence of an object without direct contact. Inductive models are used for metal parts, while capacitive models can detect other materials.
On a test bench, they are often used to secure a position, confirm the presence of a product, detect an end-of-travel position, or verify that a component is properly positioned before the test begins.
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Speed sensors
Speed sensors are used to measure the travel or rotational speed of a component during a test. They are useful when the product’s behavior depends on movement, response time, or cycle repetition.
On a test bench, these measurements can be used to monitor the speed of a shaft, track the rotation of a motor, check the movement of an actuator, or compare the consistency of a mechanism over several cycles.
Speedometers
A tachometer measures rotational speed. It can be used to monitor a motor, a shaft, a pulley, or any rotating component in a test setup.
This measurement is useful when you want to verify a rated speed, detect drift, or synchronize rotation with other parameters measured on the test bench.
Linear speed sensors
Linear speed sensors measure the speed of a moving object. They can be used on cylinders, actuators, or guided systems.
On a test bench, they help verify the repeatability of a movement, ensure compliance with a motion profile, or analyze the product’s response during a dynamic phase.
Optical sensors
Optical sensors use light to detect presence, position, distance, color, or contrast. They are often used when it is necessary to perform a non-contact measurement or to quickly check a condition during a test cycle.
On a test bench, they can be used to verify the presence of a product, detect the passage of a part, check a visual mark, or ensure a step is completed before the test begins. They are also useful when direct contact with the part is not desired.
Photocells
Photoelectric sensors detect the presence or passage of an object using a light beam. They can operate in through-beam, reflective, or direct detection modes, depending on the test bench configuration.
This type of sensor is often used to verify that a product is properly in place, count the number of passes, or trigger an automatic action in a test sequence.
Laser sensors
Laser sensors enable the precise measurement of distance, position, or displacement without coming into contact with the object. They are useful when tracking small changes or measuring fragile, deformable, or difficult-to-measure objects.
They can be integrated into a test bench to monitor stroke, check geometry, measure deformation, or track the behavior of a part during a test.
Humidity sensors
Humidity sensors measure the amount of water present in the air or in a test environment. They are useful when ambient conditions can alter the behavior of the product being tested or affect the accuracy of the measurements.
In a test bench, this type of sensor can be integrated to monitor humidity in a climate chamber, control an aging environment, or verify the conditions of a long-term test.
Why measure humidity during a test?
Humidity can affect certain materials, electronic components, bonded assemblies, plastic parts, or products exposed to varying environmental conditions. Measuring humidity allows for a better interpretation of results and helps avoid attributing a variation to the product when it actually stems from the test environment.
Measurements often associated with temperature
In many cases, humidity is monitored alongside temperature. These two parameters provide a more accurate picture of test conditions, particularly for endurance, aging, environmental performance, and long-term stability tests.
How do you choose a sensor for a test bench?
The choice of a sensor depends not only on the parameter to be measured. It must also take into account the product being tested, the type of test, the required accuracy, and the environment in which the test bench operates.
Key criteria to check
- the quantity to be measured: force, pressure, displacement, velocity, temperature, humidity, or optical signal;
- the required measurement range, with a margin appropriate for the test conditions;
- the expected accuracy and repeatability of measurements;
- the sampling rate, particularly for rapid or cyclic tests;
- the environment: temperature, humidity, water splashes, vibrations, dust, or mechanical stress;
- calibration requirements and the need for traceability of results.
On a hydraulic test bench, the focus is often on pressure, flow rate, temperature, or leak tightness. On a mechanical test bench, measurements tend to focus more on forces, displacements, cycles, or deformations.
Finally, the sensor must be compatible with the data acquisition software. The data must be able to be recorded, compared, and incorporated into a test report that can be used by quality, R&D, or laboratory teams.
Metrology and Calibration of Force Sensors
On-site inspection protocols and traceability of mechanical measurements
In the field of mechanical testing, the accuracy of fatigue, tensile, and flexural tests depends directly on the stability of the data acquisition systems. The structures of our machines incorporate specific calibration ports and mechanical mounts. These configurations allow a master reference sensor (calibration load cell) to be mounted directly in series along the axis of the thrust cylinder, without requiring the complete disassembly of the tooling or the guide frame.
The software program, developed in the LabVIEW environment, includes a native metrology module accessible via a secure administrator profile. During periodic verification tests, the operator applies a controlled load ramp across 3 to 5 points on the measurement range of the force sensor. The software instantly calculates the linear regression lines and updates the correction coefficients to eliminate potential drifts in the analog signal (4–20 mA loops or 0–10 V signals).
Each calibration cycle generates an immutable history. The results, observed deviations, and linearity curves are recorded and then automatically exported in CSV or TDMS digital formats. These files provide technical directors and quality managers with the metrological reports essential for validating certification audits and ensuring the repeatability of endurance tests on our mechanical test benches.
From Physical Measurement to Product Compliance
Force, speed, light, or humidity: Direct physical measurement is essential for validating the behavior of an industrial system. Integrating these sensors makes it possible to utilize concrete numerical data, both during R&D development testing and on production control lines.
The reliability of future test benches will depend directly on the accuracy of these instruments. Rigorous evaluation in a laboratory or workshop remains the only technical means of identifying measurement errors, validating component durability, and ensuring final compliance as required by the specifications.