Sensors & Transducers e-Digest, Vol. 55, Issue 5, May 2005: Product News
(ISSN 1726- 5479)
Hall Angle Sensor Provides all Forms of Output Signals
The iC-MA is a general-purpose magnetic angle encoder in a space-saving DFN10 package (4x4x1 mm). Its circuit comprises a number of Hall sensors for analog sine/cosine generation, as well as an integrated signal processor with an analog-to-digital converter and output interfaces. Using three configuration pins, you can choose from 26 operational modes for evaluating the postion angle of the rotary magnet mounted above the chip. Magnetic fields of at least 20 mT are sufficient for ensuring accuracy; an appropriate gain or error signal can be used for monitoring the spacing and for centering the magnet.
Working distances of several millimeters between the magnet and the package are achieved, depending on the material and size of the magnet. Apart from purely analog sine and cosine signals for determining the angle with external interpolators, the iC-MA also offers output signals processed from these with a resolution of 6, 7 or 8 bits so that one revolution can be recorded in up to 256 angle steps.
In analog form, the angle values are available as periodic sawtooth and delta voltage with arbitrarily selectable amplitudes. As digital signals, A/B quadrature encoder outputs are available with an index pulse Z as well as also up/down counter pulses for activating displays, for instance. Additional power reduction modes enable the operating current to be cut in half. Rotary frequencies of up to 60,000 rpm can be processed.
A number of iC-MA devices can be connected in cascade formation, thus enabling rotation angles on various axes to be scanned by activating the devices one after the other and output the angle signals on a 4-wire bus. This makes it easier to hook up to a microcontroller or interpolator for further processing. Deactivated modules with high-impedance bus connections are in standby mode with a very low level of standby current being drawn.
Areas of application for iC-MA are non-contact panel buttons, magnetic incremental and absolute position encoders for drive controls, for commuting brushless DC motors, as well as in the areas of robotics and mechanical engineering at industrial temperatures of between -40° C and 125° C.
Thanks to its non-contact sensor principle and large working tolerance, the iC-MA is particularly well suited to applications in which it is advantageous to hermetically separate the electronic components from the mechanical driving system, as for example in surroundings that are wet, dusty or prone to explosion.
Dr. David Lin,
Am Kuemmerling 18, 55294 Bodenheim
Tel.: 06135/9292-300, fax: 06135/9292-192
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