Linear Displacement Transducer: Types, Working Principle and Application

A linear displacement transducer, also known as a linear position sensor or linear encoder, is a crucial component in various industries and applications where precise measurement and control of linear motion are required.

In this article, we will explore the different types, working principles, and applications of linear displacement transducers and how to choose. Whether you are an engineer, a researcher, or an enthusiast in the field of motion control, understanding the capabilities and benefits of linear displacement transducers will empower you to make informed decisions when selecting the most suitable transducer for your specific needs.

What is Linear Displacement Transducer

A linear displacement transducer, also known as a linear displacement transducer or linear position transducer, is a type of sensor or measuring device used to accurately determine the linear position or displacement of an object. It converts linear motion into an electrical signal that can be used for various purposes, such as monitoring, control, or feedback in industrial and scientific applications.

Different Types of Linear Displacement Transducers (Example)

There are various types of linear displacement transducers available, each utilizing different technologies and principles to measure linear displacement. Here are some commonly used types:

1. Potentiometric Transducers: Potentiometric transducers, also known as linear potentiometers, use a resistive element and a sliding contact to measure linear displacement. The sliding contact moves along the resistive element, producing a change in resistance that corresponds to the position.

2. LVDT (Linear Variable Differential Transformer): LVDT transducers are based on electromagnetic induction. They consist of a primary coil and two secondary coils wound around a ferromagnetic core. The movement of the core due to linear displacement induces a differential voltage in the secondary coils, which is used to determine the position.

3. Magnetostrictive Transducers: Magnetostrictive transducers utilize the magnetostrictive effect, where a magnetostrictive wire generates ultrasonic waves that travel along the wire. The time it takes for the wave to reach a position is used to calculate the linear displacement.

4. Capacitive Transducers: Capacitive transducers use changes in capacitance to measure linear displacement. They typically consist of two parallel plates, one fixed and one movable. The displacement alters the capacitance between the plates, which is then converted into a position measurement.

5. Optical Encoders: Optical encoders employ light-based technology to measure linear displacement. They consist of a light source, a scale with fine markings, and a photodetector. The movement of the scale interrupts the light path, and the photodetector converts this interruption into position information.

6. Eddy Current Transducers: Eddy current transducers utilize the principle of electromagnetic induction. They generate an alternating magnetic field that interacts with a conductive target. The position is determined by measuring the changes in impedance induced by the eddy currents in the target.

How Does a Linear Displacement Transducer Work

The specific working principle of a linear displacement transducer can vary depending on the type of transducer,

LVDT sensor working principle

Linear Displacement Transducer Application

Manufacturer of Linear Displacement Transducer

Here we will introduce the manufacturers and the representative models of linear displacement transducer,

🔺Balluff:

• BTL5 Series
• BTL7 Series
• BTL Magnetostrictive Linear Position Sensor

🔺Novotechnik:

• LWG Series
• LWH Series
• TLH Series

🔺Honeywell:

• SMART Position Sensors (SRS Series)
• Micro Switch HDLS Series

🔺SICK:

• DFS60 Incremental Encoder Series
• DML/E Distance Measurement Sensors
• LMS100/LMS111 Laser Measurement Sensors

🔺Turck:

• LRS Series
• LR Linear Position Sensors
• LTX Series

🔺Heidenhain:

• LS Series
• LIP Series
• RCN Series

🔺Micronas:

• HAL 15xy Series
• HAL 37xy Series
• HAL 8xy Series

🔺AMS:

• AS5311 Linear Position Sensor
• AS5410 Hall Effect Position Sensor
• AS5600 Magnetic Rotary Position Sensor

🔺MTS Sensors:

• Temposonics E-Series
• R-Series
• G-Series

🔺Positek:

• PIPS Series
• PL Series
• P101 Series

🔺RLS (Renishaw):

• RGH41 Series
• RLS-C Series
• RMB20 Series

How to Choose Linear Displacement Transducer

Choosing the right linear displacement transducer depends on several factors. Here are some key considerations to help guide your selection:

1) Measurement Range: Determine the range of linear displacement you need to measure. Ensure the transducer has a measurement range that covers your required distance.

2) Accuracy: Consider the level of accuracy required for your application. Different transducers offer varying levels of accuracy, so choose one that meets your precision requirements.

3) Resolution: Determine the smallest increment of displacement you need to measure. Transducers with higher resolution provide finer measurement increments.

4) Environmental Conditions: Assess the environmental conditions in which the transducer will operate. Consider factors such as temperature, humidity, vibration, and exposure to dust, chemicals, or moisture. Choose a transducer that is suitable for the specific environmental conditions.

5) Mounting and Integration: Consider the mechanical aspects, such as the mounting options and compatibility with your existing system or equipment. Ensure the transducer can be easily integrated into your setup.

6) Output Signal: Determine the type of output signal required for your application. Common options include analog voltage, analog current, digital (such as PWM or SSI), or serial communication. Ensure the transducer's output signal is compatible with your control or measurement system.

7) Reliability and Durability: Consider the reliability and durability of the transducer, especially if it will be subjected to harsh operating conditions or high levels of vibration. Look for robust construction and protection against environmental factors.

8) Cost: Evaluate your budget and consider the cost-effectiveness of different transducer options. Remember to balance cost with the required performance and features.

9) Application-specific Features: Depending on your application, you may need specific features such as non-contact measurement, intrinsic safety, compact size, or compatibility with certain protocols. Identify any application-specific requirements and ensure the chosen transducer meets those needs.

Conclusion

In conclusion, linear displacement transducers play a vital role in achieving precise measurement and control of linear motion in various industries and applications. Their ability to convert mechanical displacement into electrical signals enables real-time monitoring and accurate control, enhancing the performance and efficiency of linear motion systems. When selecting a linear displacement transducer, it is important to consider factors such as resolution, accuracy, operating range, and environmental conditions to ensure optimal performance.

Stay updated with the latest advancements in transducer technology, explore datasheets and technical documentation, and make informed choices when incorporating linear displacement transducers into your projects. Embrace the precision and reliability offered by these transducers, and unlock new possibilities in achieving precise linear motion control in your applications.