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Interpolation unit AM-IPE-Nonius

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The 2-channel interpolation unit AM-IPE-Nonius is used to increase the resolution for absolute distance and angle measuring systems with 2 sinusoidal output signals (vernier signals) phase-shifted by 90 ° and to calculate the absolute position of the sensor from the two vernier signals. One or two-channel incremental position and angle measuring systems can also be connected. The integrated vernier interpolation circuit GC-NIP divides the sine periods of the input signal into up to 8192 increments to calculate the incremental position of both channels, as well as the absolute position determined by means of vernier calculation. The position resolution is accurate up to 22 bits. In order to increase the accuracy of the absolute position, a set of sensor-specific and scaling-specific coefficients can be stored in the EEPROM of the GC-NIP. The input signals are subjected to an AMAC-specific gain and offset correction. Furthermore, the phase shift of the input signals can be corrected statically using a digital potentiometer.

The noise of the sensor signal is prevented by an analog low-pass filter. In addition, a digital hysteresis suppresses the edge noise of the output signals at low frequencies and at standstill. As a result, a subsequent interpolation counter works without errors even in the event of brief disturbances in the input signal. The position signal can be transmitted to downstream components via the SPI interface, SSI interface, BiSS interface or as a conventional ABZ square wave signal.

The quality of the signal provided by the sensor is monitored by the GC-NIP inside the AM-IPE-Nonius. For this purpose it is possible to monitor up to nine potentially occurring sources of error separately. This means that harmonics of the sine signal or inaccuracies in the scaling do not lead to errors in the absolute position value. The correct coefficients are determined using a simple software-based calibration procedure.
Encoders or measuring bridges with voltage interfaces can be connected directly. Sensors with a current interface and photodiode arrays are adapted using a simple external circuit. The interpolation unit works with both single-ended and differential input signals.

Since the AM-IPE-Nonius provides absolute position and also incremental square-wave signals in parallel, it is predestined for use in motor control systems. The four integrated output interfaces (ABZ, SPI, SSI, BiSS) and other features such as the multi-stage trigger, the processing of distance-based reference marks, the possibility of setting the reference point and the storage of the zero position enable the unit to be used directly in industrial applications Controls or in fast absolute or multi-channel incremental position measuring systems.

Activating the SPI master enables the user to modify the SSI / BiSS data and to enrich it with external data from multiple counters or error information.

The AM-IPE-Nonius can be configured via USB, SPI or BiSS interface or from the circuit's EEPROM. The interpolation unit can be connected to standard counters or controls via RS422. In addition to SPI, it is possible to activate the SSI / BiSS mode via USB and connect the unit to an SSI / BiSS master.


Analog input
Sine / cosine / reference signal; differential or single-ended
Vernier amplitude configurable to 660mVpp / 250mVpp / 120mVpp / 60mVpp
Maximum input frequency 130 kHz for the vernier calculation
Maximum input frequency 90 kHz for interpolation
ABZ 90 ° square wave signals (A / B / Z)
Adjustable width of the zero signal Z between 1/4 and 1 period A / B
Error signal
Interrupt signal for external processes
Auxiliary signals for sensor setting
SPI 30 bit counter value for the interpolation channels
up to 22 bit resolution of the absolute position
9-bit sensor status information for each channel
Compatible with standard SPI: 16 bit, MSB first, up to 15 MHz
SSI und BiSS 30 bit counter value
2 bit sensor status
Gray code / binary code
adjustable timing
SSI ring operation
BiSS up to 10 MHz, SSI up to 5 MHz
Additional inputs
Trigger input for saving the measured value
Preset signals for setting and storing the counter values
Alignment of the reference position by means of an external signal
Configurable options integrated EEPROM
Configuration inputs
Serial interface (SPI / BiSS)
Interpolation / Nonius calculation / signal processing
Interpolation rate 256 to 8192, dividable by 8
adjustable divider 1/2/4/8 for A/B-signals of each channel
Vernier graduation Interpolation rate / [8 / 16 / 32 /64]
Vernier correction Correction values in the EEPROM
software-based calibration process to determine the correction coefficients
Signal correction AMAC-specific digital controller for offset, control range ± 10% of the nominal amplitude
AMAC-specific digital controller for amplitude, control range factor 60% ... 120% nominal amplitude
Digital potentiometer with 64 steps for phase correction; Adjustment range ± 5 ° or ± 10 °
Monitoring and assessment of the quality of the input signals
The behavior of the IC in the event of sensor errors can be programmed
Interference suppression Adjustable low pass 10 kHz, 75 kHz, 150 kHz
Digital hysteresis to suppress the edge noise at the output (0 ... 7)
Adjustable minimum edge separation (bandwidth limitation) at the output
Reference signal processing Adjustable reference point position in 32 steps 0… 360 °
optional: precise angle configuration of the reference point position
Determination of the optimal reference position via SPI
Processing of distance-coded reference marks
Measured value triggering at the reference point position
Output signals 30-bit counter value via USB, serial interface (SPI) optional
Frequency of the edge change (A / B / Z) maximum 24 MHz
90 ° rectangular sequences (A / B / Z)
Error signal
Auxiliary signals for the sensor adjustment
RS422 interface
Signal correction Freely definable support point correction (up to 1024 support points)
AMAC-specific digital controller for offset, control range ± 10% of the nominal amplitude
AMAC-specific digital controller for amplitude and offset
Digital potentiometer with 40 steps for phase correction;
Selectable setting range ± 5 ° or ± 10 °
LED control signal
Configuration options USB, EEPROM or optional serial interface (SPI)
Optional SPI interface Compatible with standard SPI: 16 bit, MSB first
SPI - clock up to 25 MHz
For configuration and output of measured values; is not required for minimal systems
5V interface
Miscellanious Simple SPI master can be activated for outputting and manipulating BiSS / SSI data
2-stage measured value trigger
Delay between sampling and measured value constant for all resolutions: Count value (both channels): 4.4µs,
Vernier scale: 8µs
Important characteristics
Operating voltage 5VDC
Temperature range -40...85°C
Housing Continuous cast profile 55 mm x 100 mm x 24 mm Mounting bracket, IP20, Connector HD-SUB-D 26-pin, mini USB




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Ordering information

Product type Description Article number
IPE Nonius Interpolation unit with GC-NIP