AEAS-7000 Datasheet, PDF (1/8 Pages) Agilent(Hewlett-Packard) – Plug and Play Ultra-Precision Absolute Encoder 16-bit Gray Code

Agilent AEAS-7000
Plug and Play Ultra-Precision
Absolute Encoder 16-bit Gray Code
Data Sheet
Description
The encoder IC consists of 13
signal photo diode channels and
1 monitor photo diode channel
and is used for the optical
reading of rotary carriers (i.e.,
discs). The photodiodes are
accompanied with precision
amplifiers plus additional
circuitry.
The monitor channel is used to
drive a constant current source
for the highly collimated IR
illumination system.
Functional Description
Background
The 13 signal channels are set up
as:
1. Two precision defining signals
(A0, A09), which are two 90°
electrical shifted sine, cosine
signals. These signals are
conditioned to be compensated
for offset and gain errors.
After conditioning they are on
chip interpolated (4 bit) and
computed to an absolute 6 bit
Gray code. Additionally, these
Sin/Cos signals can be tapped
as two true-differential analog
outputs to be used at the
system designer’s choice.
2. 11 analog (A1-A11) channels
which are directly digitized
by precison comparators with
hysterisis tracking. The
digitized signals are called
D1-D11.
An internal correction and
synchronization module allows
the composition of a true 16 bit
gray code by merging the data
bits of 1) and 2) by still keeping
the code monotony.
There is a Gray code correction
feature for this encoder to
counter any codewheel
imperfection or misalignment.
This Gray code correction can
be disabled/enabled by the pin
KORR.
The gain and offset conditioning
value of the sine and cosine
wave has been on-chip preset
by factory. This will
compensate for mechanical
sensor misalignment error.
Features
• Minumum mechanical alignment
during installation
• 2 Sine/Cosine true differential
outputs with 1024 periods for unit
alignment
• Integrated highly collimated
illumination system
• 11 digital tracks plus 2 sin/cos
tracks generate precise 16 bit Gray
code
• Ultra fast, 1 µs cycle for serial data
output word equals 16 MHz
• On-chip interpolation and code
correction to compensate for
mounting tolerance
• MSB can be inverted for changing
the counting direction
• Internally built in monitor track for
tracking the light level
• Watch dog with alarm output
• –25°C to +85°C operating temp.
Applications
• Rotary application up to 16 bit/
360° absolute position
• Rotary application up to 11 bit user
defined code patterns
• Cost effective solution for direct
integration into OEM systems