1
INTRODUCTION
LISST-AOBS
system parts
The LISST-AOBS is a system with three main parts:
1.
LISST-ABS acoustic backscattering sensor
2.
Turner Designs
Turbidity Plus™
optical backscattering sensor
3.
A Y-cable/adapter connecting the two sensors.
The combination of acoustic and optical sensors provides measurements
of total s
concentration that are much less affected by particle
size than standard turbidity measurements (see
on page 21).
For complete technical details of the
Turbidity Plus™, see the User’s
https://www.turnerdesigns.com/turbidity-plus-submersible-
Data outputs
The LISST-AOBS has three outputs:
1.
ABS standardized concentration in mg/liter, as calibrated with 75-
90 µm microspheres.
2.
Turbidity Plus output in Volts (
not
calibrated in terms of
concentration or NTU).
3.
AOBS concentration (Super-Turbidity) in mg/liter, a combination
of the ABS and OBS measurements as described in
on page 22.
Data interface
and logging
options
LI T-AOBS has two digital interfaces: RS-232 and SDI-12. Both interfaces
are available for communication at any time, although normally you will
communicate using only one interface at a time. NOTE: the RS-232
interface will not respond when an SDI-12 command is in progress.
Any logger that supports SDI-12 version 1.3 or higher can use the SDI-12
interface. Sequoia has teamed with NexSens Technology to integrate the
LISST-AOBS with the NexSens X2 logger family, using SDI-12. The X2 can
automatically detect a LISST-AOBS and deliver its data, with data from
other connected sensors, through Wi-Fi, cellular, radio, or satellite
channels. See more in
Operation with the NexSens X2 logger
on page 4.
If operating with a logger other than the X2 family, see
on page 7. For details of the RS-232 interface, see
starting on page 9.
