Targeting industrial applications, Analog
Devices’ ADIS16209 dual-axis inclinometer
and accelerometer breaks new ground
in price, performance, size, and ease of
use. The company claims this highly integrated
device is the industry’s most accurate and easy-touse
tilt sensor. It’s also 100 times smaller than other
available devices.
The ADIS16209 offers a fully compensated
direct digital output with less than 0.1° of linear inclination
error. That makes it about three times as accurate as competitive
tilt sensors, according to ADI. To boot, the company says
that it has one-tenth the price tag of functionally equivalent
competitive units.
The ADIS16209’s core is based on ADI’s dual-axis ADXL203
MEMS accelerometer. Its dimensions are a mere 9.2 by 9.2 by
3.9 mm, available in a laminate-based land-grid array (LGA)
package (Fig. 1). Many alternative tilt sensors make use of
bulky fluid-filled electrolytic sensors, which can require special
board mounting.
“While there are other inclinometers available that are fully
calibrated, these are much larger in size. There are also many
other small-size units, but these require extensive
calibration procedures,” explained Bob Scannell,
iSensor Business Development Manager for Analog
Devices.
The ADIS16209’s small size enables users to place the
device right at the point of applications, simplifying its use. It
features dual-mode operation either as a dual-axis inclinometer
with a ±30° range (operable to within ±90°) or a single-axis
vertical mode within a ±180° range. It operates from a single
3.3-V power supply and typically dissipates 11 mA. The product
is designed to withstand 3500-g shocks as well.
An embedded controller
The ADIS16209’s serial
peripheral interface (SPI) enables simple integration into most
industrial system designs. Thanks to an embedded controller,
the chip is fully compensated for variances in bias, sensitivity,
power-supply levels, cross-axis sensitivities, axial misalignment,
non-linearity, and temperature drift (Fig. 2).
Unlike other units on the market, which typically feature an
analog acceleration signal output, there’s no need for users to
perform sometimes extensive calibrations and adjustments.
The tunable 14-bit digital sensor output data provides access
to inclination (within 0.025° resolution) and acceleration (within
0.244-mg resolution). A simple internal register structure
handles all output data and configuration features.
Other features include typical low accelerometer noise of
1.7 mg rms and typical noise density of 0.17 mg/vHz rms. Offset
error is rated within ±4 least-significant bits (LSB), and gain
error is within ±2 LSB. Figure 3 shows a plot of the unit’s inclination
accuracy as a function of acceleration accuracy.
Additional features include typical alignment error (X sensor
to Y sensor) of ±0.2°, an acceleration frequency bandwidth of
50 Hz, and a resonant frequency of 5.5 kHz. The ADIS16209 is
rated for operation over the –40°C to 85°C temperature range.
The accelerometer’s output in the self-test mode ranges from a
minimum of 706 LSBs to a maximum of 1973 LSBs at 25°.
“The ADIS16209 provides an accurate and simple bits-out
angle in a standard semiconductor format. This is a big departure
from both electrolytic and less integrated MEMS-based sensors,” said Andy Garner, product line
director for Analog Devices’ iSensor intelligent
sensor products.
“The on-chip dynamic compensation of
the ADIS16209 is important for two reasons.
It allows our customers to confidently
absorb mid-stream system design
changes without losing their time-to-market
advantage, and it provides end users
with equipment that delivers accurate
sensing data that is resistant to in-field
environmental changes that can often
result in costly, cumbersome recalibration,”
Garner added.
One important feature is its programmable
condition monitoring. Configurable
operating parameters include
sampling rate, power management, digital
filtering, auxiliary analog digital outputs,
offset/null adjustments, and selftesting
for the integrity of the sensor’s
mechanical structure.
The inclinometer’s combination of features
makes it a natural for a host of
industrial applications. These include
surveying equipment, factory machine
tools, satellite-antenna stabilization systems,
robotics, motion-safety monitors
for medical and security systems, and
automotive wheel alignment.
Samples of the ADIS16209 sensor are
available now at a price of $34.40 each
in 1000-unit quantities. A complete evaluation
board, the ADIS16209EVAL, is
available for about $175. It includes a
board-mounted sensor, interface hardware,
and evaluation software. Volume
production quantities are expected
sometime this month.
Analog Devices
www.analog.com