Dual angle sensor demo board for magnetic on-axis encoder

27th May 2020

iC-Haus

Alex Lynn

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The new dual angle sensor demo board PVL3M has provided an XMR sensor (AMR angle sensor AA746C from Sensitec) in combination with the multiturn Hall sensor iC-PVL from iC-Haus for on-axis absolute angle measurement and revolution counting.

Evaluation of the two sensors is performed by the new 26-bit encoder signal processor iC-TW29 with integrated EEPROM. The sine/cosine signals from the XMR sensor are processed in the chip, interpolated, and output with an arbitrarily selectable single-turn resolution.

The iC-PVL provides battery-backed multiturn position to the iC-TW29 via its Absolute Data Interface (ADI). This combination can be used to make a magnetic multiturn serial absolute encoder. For example, a BiSS encoder with an angular resolution of 17 bits and 24 revolution counting bits is possible. Signal processing time is only 5 µs, which is very close to that of optical encoders.

Simultaneously, Auto Calibration in the iC-TW29 corrects the sine/cosine signal errors ensuring high measurement accuracy over temperature or with axial play of the motor shaft.

Position output via SPI or incremental quadrature signals with index at any arbitrary resolution (FlexCount) from one to 32,768 CPR is also possible.

Requiring a single-sided supply of +3.3, the sensors as well as the iC-TW29 operate over an industrial operating temperature range of -0 to +125°C. As for external circuitry, only a few components are required; typically just a voltage regulator and a transceiver for data communication (BiSS/SSI) are needed.

The iC-TW29 is housed in a space-saving 32-pin QFN package which requires only 5x5mm on the PCB. For sampling purposes, ready-to-use demo boards (which can also serve as programming adapters) and a PC operating program (GUI) are available.