iC-MQ PROGRAMMABLE 9-BIT
Sin/Cos INTERPOLATION IC WITH RS422 DRIVER
Rev D4, Page 2/39
DESCRIPTION
Interpolator iC-MQ is a non-linear A/D converter A control signal is generated from the conditioned
which digitizes sine/cosine sensor signals using a signals which can track the transmitting LED of op-
count-safe tracking conversion principle with se- tical encoders via the integrated 50 mA driver stage
lectable resolution and hysteresis. The angle reso- (output ACO). If MR sensors are connected this
lution per sine period can be set using SELRES; up driver stage can also track the power supply of the
to 400 angle steps are possible (see page 26).
measuring bridges. By tracking the sensor energy
supply any temperature and aging effects are com-
The angle position is output incrementally by differ- pensated for, the input signals stabilized and the ex-
ential RS422 drivers as an encoder quadrature signal act calibration of the input signals is maintained. This
with a zero pulse or, if selected, as a counter signal enables a constant accuracy of the interpolation cir-
for devices compatible with 74HC191 or 74HC193.
cuit across the entire operating temperature range.
The zero pulse is generated electronically when an When control limits are reached, these can be indi-
enable has been set by the X1/X2 inputs. This pulse cated at the maskable error pin ERR. Faults such as
can be configured extensively: both in its relative po- overdrive, wire breakage, short circuiting, dirt or ag-
sition to the input signal with regard to the logic gating ing, for example, are logged.
with A and/or B and in its width from 90° to 360° (1/4
to 1 T).
iC-MQ includes extensive self-test and system diag-
nosis functions which check whether the sensor is
A preselectable minimum transition distance permits working properly or not. For all error events the user
glitch-free output signals and prevents counting er- can select whether the fault be displayed at error pin
rors which in turn boosts the noise immunity of the ERR or the outputs shutdown. At the same time er-
position encoder.
rors can be stored in the EEPROM to enable failures
to be diagnosed at a later stage. For encoder ap-
Programmable instrumentation amplifiers with se- plications the line count of the code disc, the sensor
lectable gain levels allow differential or single-ended, signal regarding signal level and frequency and the
referenced input signals; via input X2 the external ref- operating temperature can be monitored, for exam-
erence can be used as reference voltage for the off- ple, the latter using an adjustable on-chip sensor.
set correction.
Display error pin ERR is bidirectional; a system fault
The modes of operation differentiate between high recognized externally can be recorded and also reg-
impedance (V modes) and low impedance (I modes). istered in the error memory.
This adaptation of the iC to voltage or current signals
enables MR sensor bridges or photosensors to be di- iC-MQ is protected against reverse polarity and of-
rectly connected up to the device. The optical scan- fers its monitored supply voltage to the external cir-
ning of low resolution code discs is also supported by cuit, thus extending the protection to the system (for
the reference function of input X2; these discs do not load currents to 20 mA). Reverse polarity protection
evaluate tracks differentially but in comparison with a also covers the short-circuit-proof line drivers so that
reference photodiode.
an unintentional faulty wiring during initial operation
is tolerated.
The integrated signal conditioning unit allows signal
amplitudes and offset voltages to be calibrated accu- On being activated the device configuration is loaded
rately and also any phase error between the sine and via the serial configuration interface from an exter-
cosine signals to be corrected. The channel for the nal EEPROM and verified by a CRC. A microcon-
zero signal can be configured separately.
troller can also configure iC-MQ; the implemented in-
terface is multimaster-competent and enables direct
RAM access.
ICHAUS [ IC-HAUS GMBH ]
