This magnetoresistive (MR) technology is ideal for implementing read-head redundancy. The MACCON MR-Encoder has been developed for the measurement of absolute position in extreme physical environments with a resolution up to 19 Bits. It is especially suited for use in Aircraft and Space and is undergoing full space-rating qualification to ESA standards.

Summary of the benefits of the MR-encoder:

• Fully passive with no integrated electronics, based on the GMR effect (Giant magnetoresistance) Only potentiometers, resolvers and Inductosyn© are comparable in terms of reliability
• Due to its simplicity and passive structure the MR encoder is highly robust and reliable
• Encoder rings can be scaled to fit the application; hollow-shaft designs are easily implemented
• Highly flexible with regard to positioning and mounting of reading head(s)
• Accurate, light and low power consumption
• Measurement is absolute over 360° (temporary position loss is immediately corrected) using the Nonius principle.
• Incremental measurement requires one tooth-ring only
• Duplication of reading heads allows direct implementation of multiple redundancy
• Insensitive to environmental influences, such as magnetic and radiation fields, as well as to temperature and shock
• Very high signal bandwidth (>> 1 MHz), ideal for precise position measurement at high speed, excellent servo-loop response

Please download the datasheet on the right-hand side, for more information, or contact us to discuss your requirements.

Our Inductosyn encoders, which have proven themselves for 60 years in space, in aircraft and on ships, are suitable for harsh environments and high measuring accuracy.

Technology:

•  Both rotary and linear versions
•  Operating principle: inductive (according to the resolver principle)
•  High pole count, therefore much more accurate than resolvers (typically <10", independent of temperature)
•  Electrical interface similar to resolver: sine excitation at approx. 10kHz, evaluation via R/D converter
•  Incremental or absolute angle or displacement measurement
•  Can be mounted directly on the axis of rotation
•  Optimum adaptation possibilities to different environmental conditions due to different substrate materials (steel, aluminium, glass, ceramics etc.)
•  Can be used at very low to very high temperatures and/or in ultra-high vacuum at very high pressure
•  Non-contact design, i.e. no wear (no lubrication or adjustment required), extremely reliable and durable

We also offer the well-known wound resolver as a space-rated variant (see picture on the right). Less well known, however, is the reluctance resolver, which has certain advantages and disadvantages over the wound resolver. See table further below for a comparison of the two technologies.

The variable reluctance resolver (VRR) consists of a rotor and stator (see picture on the right). The stator consists of insulated copper wire windings (primary and secondary) wound on laminated silicon steel. The rotor is oval-shaped and consists only of laminated silicon steel. The oval shape of the resolver causes a change in reluctance when the rotor revolves inside the stator. This change in reluctance can be used to detect the rotor angle. In contrast to conventional resolvers (rotor and stator both wound), reluctance resolvers have both primary and secondary windings on the stator and do not need a winding in the rotor. This offers many advantages in terms of cost, mass and space requirements. The variable reluctance resolver weighs less, has a shorter axial length and costs less than a conventional resolver.

We manufacture our reluctance resolvers in-house using ESA-certified materials (e.g. a low outgassing potting compound for the stator winding, nickel-plating of stator/rotor lamination stack). We can also offer a redundant stator winding if required. We offer resolvers with different inner and outer diameters.

These are mainly directly integrated in the motor windings and are only used for commutation or can be used for simple speed or position control tasks.