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.

2.4 Automatic magnet strength adaptation

In order to improve signal quality and system compatibility, GB sensors are equipped with automatic gain control function. It can automatically adjust the signal amplification factor based on the magnetic field strength of the position magnet used, ensuring stable signal output throughout the entire measurement range. This simplifies on-site debugging and allows users to choose magnet types within a certain range.

2.5 Programmable measurement range

The starting and ending points of the sensor (i.e. zero and full range) can be programmed and modified through standard connecting cables after installation, without the need to remove the sensor or use a dedicated programmer. This provides great flexibility for adjusting the travel range on site.

Model and electrical interface configuration

The GB series offers three different electrical connection options to accommodate different installation and protection needs:

3.1 GB-N: M12 A coded circular connector (5-pin)

Connector model: M12 A code, straight head or elbow (specified when ordering).

Features: Industrial automation standard interface, easy to plug and unplug, protection level IP67 (when tightened correctly).

Recommended tightening torque: 0.6 Nm.

Working temperature: -30 ° C to+85 ° C.

Material: Nickel zinc alloy (GD Zn), contact plug made of brass.

Typical applications: General industrial environments that require quick connection/disconnection.

3.2 GB-K: M16 Circular Connector (6-pin)

Connector model: M16, straight head or elbow.

Features: More sturdy than M12, usually used for thicker cables or situations requiring higher mechanical strength.

Protection level: IP65/IP67 (when tightened correctly).

Tightening torque: 0.6 Nm.

Working temperature: -40 ° C to+100 ° C (straight head)/-40 ° C to+95 ° C (elbow).

Material: Nickel zinc plating.

Typical applications: heavy industry, hydraulic systems, mobile machinery.

3.3 GB-J: Direct cable lead out

Features: The sensor comes directly with a length of cable and cannot be disassembled. Provide the highest sealing reliability, suitable for long-term fixed installation and environments that are not easily pulled by external forces.

Protection level: IP65/IP67.

Cable type: optional PUR, Teflon or silicone sheath (see cable section below for details).

Typical application: Fixed equipment inside the control cabinet or that does not require frequent disassembly and assembly.

Analog output signal

The GB series provides standard analog current or voltage outputs for direct connection to PLCs, controllers, or display instruments.

Current output: 4-20 mA (two-wire or three wire system, depending on the model). It has the advantage of resisting long-distance transmission interference and is suitable for applications with long signal lines.

Voltage output: 0-10V or 0-5V (three wire system). Suitable for controllers with short distance and low impedance inputs.

The internal digital measurement values are converted into analog signals through a 16 bit D/A converter, ensuring high-resolution and smooth output characteristics. Users can set the output values corresponding to zero and full range using programming tools or on-site programmers, such as mapping 0-500 mm stroke to 4-20 mA.

Cable and programming tools

5.1 Standard Cable Options

When choosing the GB-J (cable outlet) version, the following three types of cables can be selected:

PUR cable (code H): Orange sheath, twisted pair with shielding, highly flexible. Suitable for conventional industrial environments, oil resistant and wear-resistant. The working temperature ranges from -30 ° C to+80 ° C.

Teflon cable (code T): Black Teflon sheath, twisted pair with shielding, flexible. It has an extremely wide temperature range (-100 ° C to+180 ° C) and is resistant to chemical corrosion. Suitable for extreme temperature or corrosive media environments.

Silicone cable (code V): Red silicone sheath, twisted pair with shielding, highly flexible. Temperature resistance range -50 ° C to+180 ° C, while maintaining excellent flexibility. Suitable for high temperature movement or situations that require frequent bending.

5.2 Programming Tools

The GB series supports two programming methods for setting parameters such as travel start point, end point, output direction, etc.:

Handheld programmer (part number 253 124): a portable device that connects to sensors through a connector and allows for intuitive "teach in" through buttons. Users only need to move the magnet to the desired starting and ending positions, and press the corresponding buttons to complete the programming. Very suitable for on-site single sensor debugging.

Control cabinet programmer (part number 253 408): can be permanently installed on a standard 35mm DIN rail with a "Program/Run" toggle switch. Suitable for applications that require frequent switching of travel ranges or batch configuration of sensors. This programmer can be connected to multiple sensors through a D-Sub interface.

In addition, MTS Sensors also provides a programming kit (part number 254 555), which includes an interface conversion box, power supply, multiple connection cables (M12, M16, terminal clips), and USB cables. Users can download configuration software for free from the official website and set parameters through a PC.

Summary of Technical Specifications

Parameter values

Measurement principle magnetostrictive, non-contact

Output signal simulation: 4-20 mA/0-10 V

Resolution 16 bit D/A conversion

Linearity ≤± 0.02% F.S. (full range)

Repetitive accuracy ≤ ± 0.005% F.S

The measurement range is customized according to the order code, typically ranging from 50 to 2500 mm

Working temperature (electronic head) -20 to+85 ° C (standard), -40 to+100 ° C (high temperature option)

The maximum pressure resistance of the sensing rod is 350 bar (depending on the model)

Protection level IP65/IP67 (when the connector is tightened correctly)

Typical supply voltage is 24 V DC (10-30 V DC)

Current consumption ≤ 50 mA (no-load)

Vibration tolerance in accordance with IEC 60068-2-6

Impact resistance in accordance with IEC 60068-2-27

EMC complies with EN 61326-1 Industrial Environment

Interpretation of Ordering Code

The ordering code for the GB series consists of multiple fields, with the following example format:

GB – N – 0100 – A – 0 – 4 – H – M – 000

Meaning of each field:

GB: Product Series (GB Series)

N: Electrical interface (N=M12; K=M16; J=cable)

0100: Measurement range (unit: mm, for example, 0100 represents 100 mm)

A: Output type (A=4-20 mA, V=0-10 V, etc.)

0: Output direction (0=positive direction, 1=negative direction)

4: Resolution/Filter Settings

H: Cable options (only valid for J version, H=PUR, T=Teflon, V=Silicone)

M: Position magnet type (M=standard ring magnet, other codes correspond to different magnets)

000: Special options (such as high temperature, ATEX, etc.)

Users need to select each item according to their application requirements, referring to the selection table in the data manual, to ensure that the sensor matches the threaded interface, stroke length, and electrical interface of the hydraulic cylinder.

Application Fields and Advantages

8.1 Hydraulic cylinder position feedback

The most common application of the GB series is to install it inside hydraulic cylinders and measure the absolute position of the piston. This can be used for:

Servo hydraulic control: closed-loop control of valve core position or cylinder speed to achieve high-precision motion.

Injection molding machine: Control the position of the injection screw and locking cylinder.

Press: Real time feedback of slider position to ensure consistent pressing depth.

Wind power generation: blade angle feedback of the variable pitch system hydraulic cylinder.

8.2 Valve actuator

The flat and compact electronic head and lateral outlet make the GB sensor very suitable for installation inside valve actuators (such as pneumatic, hydraulic, or electric actuators). The sensor rod is connected to the valve stem, which can accurately feedback the opening of the valve for process regulation or safety interlocking.

8.3 Mobile Machinery and Construction Machinery

For mobile devices such as excavators and loaders, GB sensors are vibration resistant, impact resistant, and have a high sealing level. They can be installed inside the oil cylinder to monitor the position of actuators such as the boom and bucket, achieving intelligent control and collision prevention functions.

8.4 Energy and Power Generation

High reliability position feedback is required in valve control of steam turbines, water turbines, and gas turbines. The high temperature option (+100 ° C) and high-pressure resistant rod of the GB sensor enable it to adapt to hot oil and high-pressure environments.

Installation precautions

Sealing and threading: When connecting the sensor rod to the cylinder body, a suitable O-ring or sealing gasket should be used to prevent hydraulic oil leakage. The tightening torque of threads should follow the manufacturer's guidelines.

Magnet installation: The position magnet must be installed on the piston and concentric with the sensor rod. The polarity direction of the magnet should be correct to avoid direct contact with the rod (non-contact requirement).

Cable wiring: Signal cables should be routed separately from power cables to avoid electromagnetic interference. Suggest using shielded cables and grounding the shielding layer at one end.

Programming sequence: After installing the sensor, power on and check if the output signal is normal before programming the travel range. When programming, the magnet needs to be moved to the actual mechanical limit.

Environmental temperature: If the application temperature exceeds+85 ° C, the high temperature option (-400C) must be selected, and good heat dissipation of the electronic head must be ensured.