Temposonics GB Sensor

Temposonics GB series magnetostrictive linear position sensor

Introduction: High precision position feedback in harsh industrial environments

In industrial fields such as hydraulic cylinders, valve control, and energy engineering, the accuracy, reliability, and durability of position measurement directly affect the performance and safety of the entire system. Traditional potentiometer or Hall effect sensors are often limited by contact wear, temperature drift, and insufficient accuracy, making it difficult to meet the long-term stability and high repeatability requirements of modern automation. Magnetostriction technology has become an ideal choice for hydraulic servo control and process automation due to its non-contact, wear-resistant, absolute position output, and strong anti-interference ability.

MTS Sensors (now under the Temposonics brand), as a pioneer in magnetostrictive position sensing technology, has launched the GB series analog output sensors designed specifically for the valve market and hydraulic cylinder installation. This series of sensors features a high voltage resistant sensing rod, a working temperature of up to 100 ° C, a flat and compact housing, and a lateral electrical interface, making it ideal for applications with limited space and harsh environments. This article will provide a comprehensive and in-depth technical analysis based on the official GB series data manual, covering measurement principles, structural design, technical specifications, electrical connections, programming tools, and selection codes.

Magnetostriction measurement principle: Time of flight method lays the foundation for high precision

Temposonics sensors use proprietary magnetostrictive technology, with the core consisting of a ferromagnetic waveguide, a position magnet, a strain pulse converter, and corresponding signal processing electronic circuits. The position magnet is connected to the measured moving part and is non contactly fitted onto the sensor rod (containing a waveguide wire), moving with the target.

The measurement process is as follows:

The electronic circuit applies a short-term current pulse to the waveguide wire.

The current pulse generates an instantaneous radial magnetic field around the waveguide wire.

At the same time, the magnetic field of the position magnet also acts on the waveguide wire.

The instantaneous interaction between two magnetic fields generates a torsional strain pulse (torsional stress wave) on the waveguide wire.

The strain pulse propagates along the waveguide at a known speed of sound (approximately 2800 m/s) towards both ends.

When the pulse reaches the end of the waveguide, it is converted into an electrical signal by the strain pulse converter.

Due to the precise known propagation speed of ultrasound in waveguide fibers, electronic circuits can convert the position of the magnet and obtain linear displacement by measuring the time difference between the emitted current pulse and the received return signal.

This principle based on time of flight determines that magnetostrictive sensors have the following inherent characteristics:

Absolute position output: No need to reset or reference point, the current position is known immediately upon power on.

Non contact, no wear: The magnet has no mechanical contact with the waveguide wire and theoretically has an infinite lifespan.

High precision and high repeatability: The time measurement accuracy is extremely high, with a linearity of ± 0.02% F.S. and a repeatability accuracy in the micrometer level.

Anti pollution and anti-interference: not affected by oil stains, dust, vibration, and electromagnetic interference, very suitable for the internal environment of hydraulic cylinders.

Design Features of GB Series Sensors

The GB series is designed specifically for built-in installation of hydraulic cylinders, while also meeting the demands of the valve market for compactness and high temperature performance.

2.1 High voltage resistant sensing rod

The sensing rod of the sensor is made of high-pressure resistant stainless steel material, which can directly withstand the system pressure inside the hydraulic cylinder (usually up to 350 bar or higher). The internal packaging of the rod includes waveguide wires and magnetostrictive elements, while the external is isolated from hydraulic oil to ensure long-term reliability. During installation, the sensor rod is screwed into the cylinder body through the cylinder head thread (such as M18 × 1.5), and the position magnet is installed on the piston and moves back and forth with the piston.

2.2 Flat and compact electronic head

Unlike traditional cylindrical sensors, the GB series electronic head adopts a flat design with significantly reduced height, and the electrical interface is located on the side (lateral outlet). This shape is very suitable for installation positions with limited side space, such as valve actuators. The electronic head material is aluminum or stainless steel, with a protection level of IP65/IP67.

2.3 Wide working temperature range

The working temperature range of the standard model is -20 ° C to+85 ° C. For high temperature conditions, the high temperature option (code -400C) is available, which extends the working temperature to -40 ° C to+100 ° C (-40 ° F to+212 ° F), and the electronic head cover is made of aluminum to improve heat dissipation. This feature makes GB sensors suitable for hydraulic systems in hot oil or high-temperature environments.