Fast adaptation of inductive sensors to suit OEM requirements 28-04-2015 EDS Miniature Precision sensor manufacturer Micro-Epsilon UK has extended its range of inductive displacement and position sensors for medium to high volume OEM applications. Sensor geometry, mounting and electronics can be custom-engineered to suit specific OEM, R&D or machine build applications. Micro-Epsilon has custom-engineered inductive sensors for OEMs in a variety of industry sectors such as hydraulics and pneumatics, military, aerospace and defence, automotive, agricultural machinery, off-highway vehicles, household appliances and medical devices. Due to its high production capacity (up to one million sensors per year), Micro-Epsilon can deliver cost effective sensor solutions for applications where the highest standards apply. These include sensors for use in high atmospheric pressures, high temperatures and high vibrations, as well as for vacuums, hazardous (ATEX-certified) environments, and clean rooms. An extremely wide range of catalogue and modified sensors form the basis for relatively quick and simple adaptation to many custom OEM applications. Chris Jones, Managing Director at Micro-Epsilon UK commented: “Often, we come across applications where standard traditional inductive sensors and controllers are not suitable, as the technical requirements of the application cannot be met by standard catalogue inductive sensors in the marketplace. As a company, one of our strengths is having the ability to select the most suitable inductive measuring principle and then modifying the sensor to meet the exact needs of an OEM customer. For example, these modifications can include varying the measuring range of the sensor, having integral or separate electronics, changing the mechanical form factor, having the target as a sleeve or plunger in hydraulic cylinders, or providing different mounting options and interfaces. In addition to providing standard LVDT driver electronics, Micro-Epsilon can also provide miniature ASICs for medium to high volume low cost applications.” Micro-Epsilon’s induSENSOR family of inductive sensors includes six core product ranges, which are based on the inductive measuring principle, the LVDT (Linear Variable Differential Transformer) principle, or patented variants of these measuring methods. Conventional 3-coil LVDT sensors The DTA series of LVDT displacement sensors and LVDT gauges have a primary and two secondary coils, which are arranged symmetrically to the primary winding. As a measurement object, a rod-shaped magnetic core can be moved within the differential transformer. Movement of the core within the magnetic field of the coil causes a higher voltage in one secondary coil and a lower voltage in the second coil. The difference between the two secondary voltages is proportional to the core displacement. Due to the differential design of the sensor, the LVDT series has an output signal that is very stable. Gauge LVDT’s with 8mm body diameter and many custom options The LDR series of inductive sensors are constructed as half-bridge systems rather than a 3-core traditional LVDT design. This enables a short, compact design with smaller diameters. This enables lower production costs, which means the LDR sensors are also less expensive than LVDT’s. Despite the lower cost, technical advantages such as higher operating temperatures (160°C as standard) and shock rating of up to 300g (axial) or 100g (radial) are offered with the LDR series. Inductive-potentiometric sensors LVP and VIP series The LVP and VIP series of displacement sensors are patented single coil inductive sensors as opposed to a 3-coil LVDT or 2-coil LDR sensor concept. This offers a significantly improved measurement range to body length ratio, which means that for any given measurement ranges, the sensors can be up to 50% shorter. In addition, the sensor body diameter is also significantly reduced, with standard sensors having an 8mm diameter. The LVP uses an inner core as the sensor rod (similar to conventional LVDT’s), whereas the VIP uses an outer ring as the target, offering an even more compact sensor footprint. Further advantages of this sensor series include integrated sensor electronics, enabling the user to have a DC voltage supply and DC volts or 4-20mA output directly from the sensor (remote electronics is also available for OEM applications if preferred). Chris Jones continues: “Quite often, customers are replacing linear potentiometers with LVP sensors, as they offer the simple installation method of a potentiometer, yet are wear-free like LVDT’s, giving the user the best features of both technologies.” Long stroke sensors for hydraulic applications The EDS series of sensors are robust, pressure-resistant position sensors designed for hydraulic cylinder positioning or for high shock and vibration applications on mobile hydraulic systems such as off-highway vehicles. The EDS sensor uses an outer sleeve rather than an inner core, which enables the sensor to be much more robust and mechanically strong. In addition, it becomes much easier to install the sensor into the hydraulic cylinder or hydraulic system. Pressure rating of 450 bar (higher rating versions are available on request) and 300g shock rating (axial) enable almost all hydraulic positioning applications to be solved. The sensor does not need remote electronics that must be matched to the sensor. The actual electronics are extremely compact and are housed in the mounting flange of the sensor, which means that the total installation is much more compact than commonly used sensors. It is also possible to adapt the sensor housing to enable it to withstand subsea applications, for example, by modifying the sensor to incorporate a subsea connector or custom mounting flange. The latest version, the EDS miniature series, is ultra-compact with a diameter of just 3mm, which is ideal for miniature hydraulic cylinders and actuators. The sensors are manufactured from a pressure-resistant stainless steel (up to 450bar), can operate to 175°C and withstand extreme vibration and shock levels (up to 300g axial and 100g radial). The sensor electronics and signal conditioning are also extremely compact. The latest version, the EDS miniature series, is ultra-compact with a diameter of just 3mm, which is ideal for miniature hydraulic cylinders and actuators. Although the sensors have an extremely compact size, they are still as robust as the standard designs. The sensors are manufactured from a pressure-resistant stainless steel (up to 450 bar), can operate to 175°C (or 210°C) and withstand extreme vibration and shock levels (up to 300g axial and 100g radial). The sensor electronics and signal conditioning are also extremely compact.