IC-MN Datasheet, PDF (2/59 Pages) IC-Haus GmbH – 25-BIT NONIUS ENCODER WITH 3-CH. SAMPLING 13-BIT Sin/D INTERPOLATION

iC-MN 25-BIT NONIUS ENCODER
WITH 3-CH. SAMPLING 13-BIT Sin/D INTERPOLATION
Rev D1, Page 2/59
DESCRIPTION
Encoder device iC-MN is a 3-channel, simultaneous
sampling sine-to-digital converter which interpolates
sine/cosine sensor signals using a high precision
SAR converter with a selectable resolution of up to
13 bits. Each input has a separate sample-and-hold
stage which halts the track signal for the subsequent
sequential digitization. Various 2- and 3-track Vernier
scale computations (after Nonius) can be configured
for the calculation of high resolution angle positions;
these computations permit angle resolutions of up to
25 bits.
The absolute angle position is output via the serial
Interface with clock rates of up to 4 Mbit/s (SSI com-
patible; up to 10 Mbit/s with BiSS C protocol). The
RS422 transceiver required to this end is integrated
on the chip and has both a differential clock input and
a differential line driver for data output.
Programmable instrumentation amplifiers with a se-
lectable gain and offset and phase correction can
be adjusted separately for each channel; these al-
low differential or single-ended input signals. At
the same time the inputs can either be set to high
impedance for voltage signals from magneto resistor
sensor bridges, for example, or to low impedance for
adaptation and use with photosensors which provide
current signals, for instance. This enables the device
to be directly connected up to a number of different
optical and magnetic sensors.
For the purpose of input signal stabilization the con-
ditioned signals are fed into signal level controllers
featuring current source outputs of up to 50 mA (mas-
ter channel) and of up to 10 mA (for the nonius and
segment channels each). These ACOx source pins
either power the LEDs of an optical encoder or the
magneto resistor bridges of a magnetic encoder. If
the control thresholds are reached this event can be
released for alarm messaging using the serial inter-
face or the NERR output.
Both major chip functions and sensor errors are also
monitored and can be enabled for alarm indication.
In this manner typical sensor errors, such as signal
loss due to wire breakage, short circuiting, dirt or ag-
ing, for example, can be signaled by alarms.
The device features further digital encoder functions
covering the correction of phase errors between the
tracks, for example, or the zeroing or presetting of a
specific position offset for data output. Using the SSI
master also integrated on the chip position data from
multiturn sensors, provided by a second iC-MN, for
example, can be read in and synchronized.
iC-MN is protected against a reversed power supply
voltage; the integrated supply switch for loads of up
to 20 mA extends this protection to cover the over-
all system. The device is configured via an external
EEPROM.