Multiturn encoder for Linear and Rotary applications

26th October 2016

iC-Haus

Enaie Azambuja

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Datasheet

iC-PVL, a configurable Hall multiturn encoder, is a battery-buffered, economical, and space saving replacement for mechanically geared multiturn encoders. Its low current consumption (<10μA) allows the battery to last several years. A flat QFN package is used, which is only 4x4 mm², and includes integrated Hall sensors. This allows the iC-PVL to read magnetic linear scales or tapes, or discs or magnet wheels with pole widths of 1.0 to 5.0 mm.

iC-PVL can be configured for linear applications as a pure period counter. In rotary applications, the FlexCount circuitry enables 1 to 256 magnetic pole pairs to be interpreted as one mechanical rotation. The position within the rotation (angle) can also be read out in this case.

The iC-PVL can read rotational velocities of up to 15 000 RPM (with a 32 pole-pair disc or wheel) or linear motion up to 24 m/s (with a 1.5 mm pole width scale or tape).

The device switches over to battery operation automatically when power fails and continues tracking the multiturn count without disruption. A configurable battery voltage warning feature makes maintenance predictable and thus avoids downtime.

The iC-PVL counts correctly despite low battery voltage, but indicates that the battery must be changed using both the error output and the status register. Current consumption in battery operation is configurable and can be adjusted for the maximum expected acceleration of the axis being tracked.

iC-Haus offers compatible singleturn encoder components featuring a multiturn interface, including optical and magnetic encoders and interpolator ICs. Using magnetic encoders (e.g. iC-MU or iC-MHM) saves space and cost since the same magnetic target is used for both devices.

For example, the combination of iC-PVL and iC-MU provides a high-resolution magnetic hollow-shaft multiturn encoder. With a 32-pole magnetic disc, this combination provides a singleturn resolution of 19 bits and a multiturn count of 18 bits. A common iC-Haus EEPROM is sufficient to save the configuration data for this system.

iC-PVL’s mode of operation is programmable. Depending on the configuration, position data is available as AB quadrature encoder signals or as a 3-bit parallel word and over SSI or I²C. The device can be operated by a microcontroller as an I²C slave with or without a battery. In this case an external EEPROM is unnecessary.

With a supply voltage of 3.0 to 5.5 V, iC-PVL works in the industrial temperature range of -40 to 125°C. The typical battery voltage is 3.6 V.