Rugged angle sensors for vehicles

Paul Boughton

Modern vehicle manufacturers are faced with increasingly stringent safety directives and complying with these is frequently a major challenge. For example, an important requirement is to be able to identify the precise (angular) positions of a wide range of vehicle components, including support legs and telescopic stabilisers.

This kind of task requires rugged, hard-wearing, high-precision rotary sensors, utilising innovative concepts to ensure redundancy and reliability. In applications in which there is a considerable distance between sensors and the control unit, an additional consideration is to maintain high standards of signal transmission and reception. Other important criteria include ease of installation and upgradeability in the normally cramped installation space, together with generous installation tolerances. And to make matters even more difficult, solutions are called for that are not affected by wear-induced offsets. [Page Break]

Precisely in response to such applications and requirements, Contelec has developed the Vert-X 90E – an extremely slim, rugged sensor solution. This is a non-contacting rotary sensor, comprising two physically separate units: the 'magnetic actuator' and the 'sensor'. The positional encoder is a rugged, passive element, attached to the rotating object, while the active sensor is attached to a stationary object, located a certain distance from the magnetic actuator.

The non-contacting architecture ensures there is no direct mechanical linkage between the rotating axis and the actual measurement system, maintaining accurate measurement even with large radial and axial offsets of up to several millimetres. This feature becomes noticeable in the installation of the rotary sensor, since measurement remains accurate even with a wide installation tolerance range. A further point to note is that any offsets developing over the course of time have no adverse influence on the precision of angle measurement. Particularly eye-catching is the extremely slim design of the heavy-duty sensor, allowing it to be used in applications and positions that would previously have been inconceivable. To satisfy the very stringent safety requirements in terms of redundancy and data transmission, the rotary sensor can be equipped with various single-output and redundant interfaces. The Vert-X 90E rotary sensor is based on the innovative Vert-X MH-C2 technology, which provides the user with a simple means of on-site setting of index points (eg a zero point) and direction of rotation.[Page Break]

The Contelec Vert-X 90E non-contacting rotary sensor sets a new standard of angle measurement in mobile applications:

* Resolution: 12–14 bit analogue, 14–16 bit digital
* Linearity: ±1% with a maximum positional encoder offset of ±3mm radial, ±1.8 mm axial
* Operating temperature range: –40°C–85 °C
* Supply voltage: 24V (16V....35V)
* Possible interfaces: 0.5V–4.5V, 0V–10V, 4mA–20mA,
* CANopen
* Max repeatability 0.1°
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