The iC-TW28 is a general purpose 10-bit application-specific interpolator for sine/cosine signals with automatic calibration and adaption of signal path parameters during operation to maintain minimum angular error and jitter. Angular position is calculated at a programmable resolution of up to 1024 increments per input cycle. Automatic calibration and adaption (correction during operation) of sensor offset, sin/cos amplitude match, and phase quadrature is provided. Additionally, automatic calibration of gain, offset and phase of the zero inputs allows for rapid commissioning.
The iC-TW28 accepts 13mV to 2V differential Sin/-Cos input signals directly from magnetic or optical sensors – no external signal conditioning is required in most applications. The differential zero input accepts a wide range of digital and analog index gating sources such as Hall or MR sensor bridges. The Z output width, position relative to the sin/cos inputs, and synchronization to the AB quadrature outputs is fully programmable.
In addition to industry-standard incremental ABZ quadrature output, the iC-TW28 provides optional UVW commutation output modes for 1 to 32 polepair motors and SPI angle and multi-cycle readout for embedded applications. The incremental ABZ quadrature output can be generated at a frequency of up to 12MHz (20 ns edge spacing); the maximum output frequency can also be limited so as not to overwhelm connected counters or controllers.
In SPI mode, the iC-TW28 provides multi-cycle synchronization and reference mark capture functions to support absolute position systems. Higher input signal frequencies are allowed in SPI mode since the ABZ output frequency limitation is not applicable.
The iC-TW28 offers two configuration modes. Pin configuration mode provides simple, static configuration that does not require any programming or complicated calibration. Pin configuration mode uses a subset of the iC-TW28’s complete capabilities including ABZ quadrature output, a limited choice of the most commonly used interpolation (resolution) and hysteresis values, and one-button calibration. Eight resistors set voltage levels at four configuration input pins to select all operating parameters, simplifying product assembly. One-button auto calibration sets input gain and compensates sensor offset and sin/cos channel gain match and phase with just a few input cycles and then stores the compensation values to the internal
In more sophisticated applications, serial configuration mode allows access to all iC-TW28 features. Complete device configuration using the bi-directional SPI or Encoder Link ports provides access to all resolutions (including fractional interpolation), fully programmable hysteresis, and advanced noise/jitter filtering, quality monitoring, and fault detection capabilities.
The iC-TW28 requires no external components for operation. An EEPROM for storage of configuration and calibration data, and RS422 line drivers are already integrated on-chip. An integrated power-on reset circuit can be overridden by an external hardware reset signal if necessary.
Symmetry Electronics is an authorized iC-Haus distributor.