Sequoia LISST-200X User manual

LISST-200X
Particle Size Analyzer
Including
LISST-HAB & LISST-Black
User’s Manual
Version 2.2
December, 2021
2700 Richards Road, Suite 107
Bellevue, WA 98005
USA
Telephone: [phone]
Store Software
USB Card Here

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LISST-200X User’s Manual Page iii
©
This document is copyrighted by Sequoia Scientific, Inc.

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LISST-200X User’s Manual Page v
Welcome to the LISST-200X Particle Size Analyzer
Using this manual
I. LISST-200X Introduction & Quick Start provides an
overview of the LISST-200X’s operating principles and basic
functions.
II. LISST-200X Operation Details provides details and step-by-
step instructions for using and caring for the instrument.
The Appendices contain specialized details, specifications, and
information about options.
Warranty
See the product warranty at:
http://sequoiasci.com/support/warranty
Technical assistance
For technical assistance please contact your local Distributor or
Sequoia. Please include the instrument serial number with any
correspondence.
Sequoia Scientific, Inc. contact information:
Telephone: [phone]
Email: [email protected]

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LISST-200X User’s Manual Page vii
Table of Contents
I. LISST-200X INTRODUCTION & QUICK START...................................................................1
A. LASER DIFFRACTION AND THE LISST-200X............................................................................1
B. LISST-200X GENERAL DESCRIPTION ....................................................................................4
C. LISST-200X QUICK START TUTORIAL....................................................................................7
II. LISST-200X OPERATION DETAILS....................................................................................26
A. STEP BY STEP PROCEDURES...............................................................................................27
1. Installing LISST-200X Software....................................................................................27
2. Establishing Communication with the LISST-200X......................................................28
3. Saving and Evaluating Clean Water Backgrounds.......................................................29
4. Configuring Data Collection..........................................................................................32
5. Using the Small External Battery Housing....................................................................36
6. Using the Large External Battery Housing ...................................................................39
7. Offloading and Deleting Data Files from Internal Memory ...........................................42
8. Processing a Single Raw Data File ..............................................................................43
9. Batch Processing Multiple Raw Data Files...................................................................45
10. View Processed Data File ........................................................................................47
11. Data Quality Control.................................................................................................48
12. Real-Time Data Processing with LISST-200X Software..........................................50
13. Autonomous Real-time Data Processing .................................................................52
14. Collecting Data from an External Analog Sensor.....................................................55
15. Configuring the LISST-200X as a Sensor for a CTD ...............................................56
B. START AND STOP CONDITIONS.............................................................................................57
C. INSTRUMENT COMMUNICATION.............................................................................................59
D. LISST-200X COMMAND SUMMARY......................................................................................60
E. LISST-200X COMMAND DETAILS.........................................................................................61
1. Display Commands.......................................................................................................61
2. Setup Commands.........................................................................................................64
3. Acquisition/Action commands.......................................................................................69
F. PERFORMANCE OPTIMIZATION .............................................................................................71
G. INSTRUMENT MOUNTING,DEPLOYMENT ORIENTATION,STORAGE AND MAINTENANCE.............74
APPENDIX A: TECHNICAL SPECIFICATIONS...........................................................................76
APPENDIX B: PARTICLE SIZE BINS ..........................................................................................78
APPENDIX C: DATA FILE FORMATS .........................................................................................79
APPENDIX D: MATLAB DATA PROCESSING............................................................................82
APPENDIX E: CONNECTORS .....................................................................................................84
APPENDIX F: PARTICLE SHAPE MODELS ...............................................................................89
APPENDIX G: LISST-BLACK & LISST-HAB...............................................................................90
APPENDIX H: BIOBLOCK ANTI-FOULING WIPER....................................................................93
APPENDIX I: PATH REDUCTION MODULE................................................................................96
APPENDIX J: TROUBLESHOOTING & SUPPORT...................................................................103
REVISION HISTORY...................................................................................................................104

Page viii LISST-200X User’s Manual
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LISST-200X User’s Manual 1 LISST-200X Introduction & Quick Start
I. LISST-200X Introduction & Quick Start
A. Laser Diffraction and the LISST-200X
Measurement
Principle and
Optics
Particle sizing by laser diffraction is currently the most widely prevalent
method in research and industry. It is a multi-parameter measurement.
Just as a set of 3 equations can be solved for 3 unknowns, a
measurement of light scattering at multiple angles can be solved for
equally as many concentrations in different sizes. For example, the
LISST-200X measures scattering into 36 angles; consequently, one
obtains concentrations in 36 size classes of particles. This is called the
particle size distribution (PSD).
To measure scattering at multiple angles, the LISST-200X sends a
collimated beam of light into the water. Laser light scattering at an
angle from the beam arrives, through a daylight rejection filter, at the
focal plane of a receive lens at the same angle from lens axis (see
figure). Distance from lens axis in the lens focal plane corresponds to
scattering angle. The photodetectors in the LISST series instruments
are a series of silicon rings spanning 60-degree arcs. Each ring covers
a small range of scattering angles. Rings are used to achieve stability
of inversion –converting of set of multi-angle scattering measurements
to the PSD.
Notice that the laser beam itself is focused by the receive lens and
passes through a small aperture in the ring detector, centered on the
rings. This beam is sensed by a photodiode placed behind the ring
detector. This is the transmission sensor. As light is removed from the
laser beam by scattering, the beam is attenuated, i.e. the light
transmitted through water is reduced in intensity. A similar attenuation
also affects the light that is scattered by particles and sensed by ring
detectors. Thus, the transmission sensor provides a vital measurement
to de-attenuate the measured scattered light.

LISST-200X Introduction & Quick Start 2 LISST-200X User’s Manual
Clean Water
Backgrounds
Scattering originates not only from particles in the water, but also from
the water itself, and from the windows and internal optics of the LISST-
200X. This non-particle scattering constitutes a Background. (Formerly
this was called zscat, meaning scattering by zero concentration of
scatterers). Accurate measurements require subtracting the
background scattering from the total signal seen by ring detectors.
The background scattering typically changes gradually throughout the
life of the instrument, due to small changes in the laser and optics, and
wear on the exposed window surfaces. It is also very sensitive to
cleanliness of the windows. Therefore, high-quality measurements
require careful background measurements by the user. A factory
background acts as a reference for comparison. The LISST-200X
stores its factory background data in its memory, as well as the user’s
acquired background data.
Background
Quality Control
Because the background measurement is so important, the LISST-
200X firmware and software include procedures for measuring and
evaluating the background scattering. The software checks for signs of
problems such as laser degradation, optics misalignment,
contamination of data by thermal microstructure in the water used for
background, bubbles or particles in the supposedly clean water,
scratches on windows etc.
For details on the background measurement procedure, see Saving
and Evaluating Clean Water Backgrounds on page 29.
Ambient Light
Rejection
The laser diffraction method requires that the light arriving on the
detector be due entirely to scattering of light that originates with the
laser beam. Light from ambient sunlight can distort the results. The
LISST physically shields the detector from much ambient light, but not
all, so daytime measurements at shallow depths can include some
sunlight. However, the LISST-200X (starting with firmware version 1.4,
introduced in May, 2017) can measure the ambient light independently
of scattered light, and remove its effects. This Ambient Light Rejection
(ALR) function is enabled by default. Also see section 0, page 71.
Quick Estimates
of Total
Concentration
and Mean Size
Converting the LISST-200X’s measurements of scattering to PSD
requires extensive computations that are time-consuming for a small
microprocessor. However, a much simpler computation, easily done in
real time, provides estimates of the total particle volume concentration
and mean particle size. These quantities are not as accurate as the
fully-processed PSD, but are useful for quick characterization of water
conditions. For example, if used in conjunction with a CTD package in
profiling applications, the CTD software could display the concentration
and mean size as a depth profile, revealing any vertical structure in the
particle distribution. (Note that real-time interface to a CTD requires
proper configuration of the LISST-200X’s auxiliary connector; see
Configuring the LISST-200X as a Sensor for a CTD on page 56.)

LISST-200X User’s Manual 3 LISST-200X Introduction & Quick Start
The quick estimates are based on weighted sum of the net scattered
light. One set of weight factors yields the total volume concentration;
the other yields the area concentration of particles. The volume/area
ratio provides mean diameter, also known as the Sauter Mean
Diameter (SMD). Notably, SMD can be quite different from D50 in broad
or multi-modal size distribution situations. The SMD output is set to
zero in very clear waters, i.e. when transmission is above 98%,
because the SMD can become erratic when the relative scattering
signal is small. [For an explanation of this method of SMD derivation,
see: Shaped Focal Plane Detectors for Particle Concentration and
Mean Size Observations; Agrawal, Y.C. and O.A. Mikkelsen, (2009),
Optics Express, v 17, n 25, pp 23066-23077].
Calculating the
full PSD in real
time
Newer LISST-200X’s, starting with serial number 2131 (and older units
with upgraded circuitry), contain more powerful processors that can do
full PSD processing in real time. The processed data can be stored in
the instrument’s memory, or transmitted through its serial port. This is
especially useful for unattended deployments, such as buoys or remote
moorings, where it is not possible to connect a Windows computer to
the instrument for data offloads. For full details, see Autonomous Real-
time Data Processing on page 52.
Particle Shape
Models –
Spheres or
Irregular Shape
The multi-angle scattering can be interpreted via inversion as arising
from spherical particles, or from irregularly shaped particles. Provided
software gives you the choice and the resulting PSD files are named
differently to distinguish them. As to which particle model to use, we
suggest that when working with natural waters, use the irregularly
shaped model. The spherical model is appropriate only in exceptional
circumstances. For more details see Appendix F: Particle Shape
Models on page 89.

LISST-200X Introduction & Quick Start 4 LISST-200X User’s Manual
B. LISST-200X General Description
Instrument
Description
The primary measurements delivered by the LISST-200X are the small-
angle scattering properties of particles in water, the laser optical
transmission, depth, and temperature. The LISST-200X is capable of
autonomous operation when used with external batteries. Windows
software is provided to program the instrument for a specific sampling
schedule. An auxiliary connector can be configured for recording data
from an external devices such as fluorometer, or for producing
summary data (mean size and total concentration) as analog voltages.
For details of the possible configurations of the Auxiliary Port, see
Appendix E: Connectors on page 84.
After recovery of the instrument, small-angle scattering data are off-
loaded from the instrument and subsequently inverted mathematically
on a computer to produce the particle size distribution. The inversion
function is included in the Windows software. For MATLAB users,
inversion scripts are available for download from Sequoia’s website:
www.SequoiaSci.com.
The LISST-200X instrument is a laser diffraction device. It consists of
optics for producing a collimated laser beam, a specially constructed
detector array, electronics for signal pre-amplification and processing,
data storage and scheduling computer, and an external battery system.
The principal measurement—angular scattering distribution—is
obtained over 36 ring-detectors whose radii increase logarithmically
from 102 to 20,000 microns. The detector is placed in the focal plane of
the receiving lens. The rings cover an angular range from 0.00085 to
0.34 radians. This angular range corresponds to size ranges from 1.00
to 500 µm. See Appendix B: Particle Size Bins on page 78 for more
information.
The LISST-200X consists of the following parts: a solid-state diode
laser operating at 670 nm wavelength and fiber-optically connected to a
laser beam collimating system, a beam manipulation and orienting
system, a two pressure windows, a scattered-light receiving lens, the
custom designed 36-ring detector, preamplifier electronics, a ring-
selecting multiplexer circuitry, and a digital controller with data memory.
All these components are inside the black-anodized pressure housing.
The LISST-200X does not have internal batteries. Its watertight
housing need not be opened for any normal use.

LISST-200X User’s Manual 5 LISST-200X Introduction & Quick Start
Data Storage
and Interface
The LISST-200X includes high-capacity data logging and storage. The
logging functions are programmed via the provided software. It can be
programmed with different start and stop conditions as well as different
sampling rates and average durations. The data logger stores the data
in non-volatile Compact Flash memory which can be later downloaded
and processed into size distributions and concentration using the
provided software.
The data logger will also accept commands via the RS232 interfaces.
These commands can be used to program the instrument or to
exchange data with another instrument.
Depth and
Temperature
In addition to measuring the particle size and concentration, the LISST-
200X also has depth and temperature sensors. The depth sensor has
a 1000 psi full-scale range and is calibrated to 600 meters depth. A
stainless-steel fitting and tube filled with silicone oil protect the pressure
transducer from contamination and corrosion. The temperature is
measured using a high precision thermistor imbedded into a stainless
steel probe on the Connector end cap. Both values are stored
automatically in the LISST-200X data file.
External I/O Port
The LISST-200X also has an auxiliary 6-pin connector for interfacing to
other devices This port can be configured to produce analog outputs, or
to receive analog inputs.
The Analog Output Configuration allows the LISST-200X to receive
power from a CTD, and to send two analog voltages indicating the
mean size and total concentration to the CTD, while the detailed size
distribution data is stored internally for later downloading. For more
details about this application, see Configuring the LISST-200X as a
Sensor for a CTD on 56.
The Analog Input Configuration enables operation with additional
sensors such as fluorometers and turbidity sensors. It provides 12V
regulated power, and accepts two or three analog inputs (0 to 5 V) from
sensors. The digitized analog values are stored in the same files as the
LISST-200X’s particle size data. This configuration also supports the
instrument packages described in Appendix G: LISST-Black & LISST-
HAB on page 90.
Battery-powered
operation
The LISST-200X does not contain internal batteries (except a small
battery to maintain the real-time clock), but can be powered from Small
or Large Battery Housings (provided with the instrument) or an external
instrument such as a CTD.
The standard Small Battery Housing supplied with the LISST-200X
uses two NiMH rechargeable D-cell batteries to provide about 12 hours
of continuous sampling.
The Large Battery Housing holds 16 standard alkaline D-cells. For
profiling applications, where the instrument is sampling continuously,
the Large Battery Housing has about 200 hours of sampling time or 200
days of stand-by. Powering down the instrument between samples can

LISST-200X Introduction & Quick Start 6 LISST-200X User’s Manual
greatly extend the deployment times. The LISST-200X software
contains a battery life calculator on the Configuration page. This feature
provides rough estimates of the battery run time for a given sampling
program.
USB Power and
Data connection
For laboratory or tethered usage, power can be supplied through the
communications connector on the endcap. A 2-meter USB cable is
provided that will power the instrument from the computers USB port.
No additional power is required to operate the instrument.
Cables up to 50 meters can be provided to supply external power and
communication with the instrument. This can allow real-time
observation of the size distributions.
Included
Accessories
The instrument is shipped pre-aligned and tested. A small chamber is
provided for obtaining measurements of background scattered light
from optical surfaces. This background is subtracted from actual
particle scattering measurements to obtain the true particulate
scattering. Additionally, small tools used to open endcaps, spare
batteries, and communication cable is supplied so that a user need only
provide a PC running Windows.
For extended laboratory applications various chambers are available
from Sequoia.
Software is provided to communicate with the instrument, schedule an
experiment, offload the data, and invert the measurements to obtain
particle size distribution and volume concentration. For laboratory use
or for monitoring the progress of an experiment, the software can be
used for real-time processing.

LISST-200X User’s Manual 7 LISST-200X Introduction & Quick Start
C. LISST-200X Quick Start Tutorial
This section gives step by step instructions to unpack your LISST-
200X, load software, and acquire data in the lab. For more detailed
instructions on specific steps, background on how the instrument
works, or specific technical information such as cable pinouts please
refer to the full User’s manual following this Quick Start Tutorial.
Contents of
Shipping Case
Let’s assume that you are opening the LISST-200X shipping case for
the first time. Inside you will find the following:
•User’s Manual,
•USB memory card (credit card size) with the software,
•LISST-200X instrument,
•Plastic Instrument stands,
•Small Volume Test Chamber,
•USB Communications cable,
•Insulated stainless steel clamps,
•Small Battery Housing (without batteries),
•Larger Battery Housing with alkaline batteries installed,
•LISST-200X-to-Battery-Housing cable,
•NiMH batteries and charger.
Step 1: Remove
Instrument from
Shipping Case.
Start by removing the white plastic instrument stands and set them on
a flat working surface. Remove the LISST-200X from the case and set
it on the stands. The LISST-200X has two distinct ends that we will
refer to as the Optics endcap and the Connector endcap.

LISST-200X Introduction & Quick Start 8 LISST-200X User’s Manual
Optics Endcap
The optics endcap contains the optical windows that the laser beam
passes through to make a measurement. The internal optics and laser
electronics are mounted to the inside of this endcap.
Connector
Endcap
The connector endcap has three underwater connectors that are used
for communication, external power, and connecting to optional
accessories or instruments:
3-pin connector: Used for BioBlock, an anti-biofouling accessory
5-pin connector: Used for serial communication and external power.
6-pin connector: Used for analog in/out and digital in/out signals.
See Appendix E: Connectors on page 84 for a full description of the
wiring of the underwater connectors and mating cables.
A temperature sensor is located between the 3-pin and 6-pin
connectors. In the center of the endcap is an LED that blinks when the
instrument is sampling. The stainless steel fitting with small tube is the
port for the depth sensor. This fitting can be removed to allow the port
to be cleaned should sediment or salt deposit build up.

LISST-200X User’s Manual 9 LISST-200X Introduction & Quick Start
Also on the Connector endcap is a white plastic lever. This
mechanical lever has a strong magnet embedded in the plastic. This
magnet can be used to trigger a digital switch inside the instrument
which can be programmed to start and stop the LISST-200X sampling.
The final item on the endcap is the zinc anode. The sacrificial zinc
anode protects the instrument from corrosion during long periods of
time in salt water.
Step 2: Check
for Clean
Windows
At this time, check the optical windows to make sure that they are
clean. There are two windows: The receive window (or large window)
and the transmit window (or small window). Both window need to be
very clean in order to get good measurements.
The best way to check the windows is by using a flashlight. By shining
light from one side and viewing from the other the surface of the
windows can be easily checked for cleanliness.
If there is dirt or fingerprints on the windows clean them first by rinsing
them with lukewarm water and a mild soap solution (e.g. mild hand
soap, liquid dish soap) and then rinsing off all soap residue with clean,
particle free water such as deionized water, distilled water or bottled
drinking water. The windows can also be wiped clean with a soft cloth
(e.g. a lens cloth) or glass cleaner. It is not recommended to use
stronger solvents, such as acetone or toluene. Also, do not use any
abrasive cleaners or wipes. Treat the windows as you would an
expensive camera lens.
Step 3: Attach
Communication
and Power Cable
Remove the Communications cable from the plastic accessory case
within the shipping case. It is the 3 meter cable with the USB
connector on one end and the 5-pin underwater connector on the
other. Remove the underwater cap from the Communications
connector. The connectors will all look similar when the protective cap
is installed. The Communication connector is the only 5-pin connector
and is located next to the stainless steel pressure sensor fitting. After
removing the cap install the cable making sure that proper alignment
of the cable is maintained, so that the connector pins are not bent.
Plug the USB cable into the computer. Please note that USB drivers
may automatically install the first time the USB cable is plugged into

LISST-200X Introduction & Quick Start 10 LISST-200X User’s Manual
the computer. If the driver installed correctly, you should see the
green light on the USB cable blinking. For more information on
establishing and troubleshooting communication with the LISST-200X
see page 27.
Step 4: Install
the Horizontal
test chamber
Remove the Small Volume Horizontal test chamber from the
Accessory Case if it is not already installed on to the instrument. This
one-piece chamber is designed to slip between the optical windows of
the instrument such that the space between the windows can be filled
with water for testing or calibration.
We can now fill the chamber with clean, particle-free water. Sequoia
uses steam-distilled bottled water filtered through a 0.2 micron filter.
Tap water may contain too many particles and may also contain
dissolved gas that can release and form small bubbles on the optical
surfaces. Pressurized filtered water can also contain dissolved gas.
Often the best source of clean water is bottled drinking water.
Step 5: Install
LISST-200X
Software
At this point the instrument is ready to go. We now need to install the
software that is required for operation of the instrument. A USB
memory card the size of a credit card is included with each instrument.
In addition to the communication and processing program the disk also
contains digital copies of this manual and other support files. Insert the
memory card into a USB port on your PC to install the software. You
must install the software on a computer running Windows XP or later
(it is not compatible with Mac or Linux operating systems).
On the memory card you will find the ‘LISST-200X_Installer.exe.’
Double click the installer executable to begin installing the software.
Follow the onscreen instructions and the installer will transfer the
necessary files to your computer and place a shortcut on your desktop
and start menu. Do not remove the memory card from your computer
until the installation is fully completed.

LISST-200X User’s Manual 11 LISST-200X Introduction & Quick Start
Please note the following with respect to the LISST-200X software:
•On a 64-bit Windows PC, the software will be installed in the
following folder: C:\Program Files (x86)\Sequoia\LISST200X,
while on 32-bit Windows machines, the install folder will be
C:\Program Files\Sequoia\LISST200X
•The LISST-200X software WILL NOT work with the older
LISST-100 or LISST-100X instruments. It is NOT possible to
use the program to offload data from a LISST-100 or LISST-
100X instrument, only a LISST-200X will work with this
software.
Step 6: Start
LISST-200X
Application
Start the LISST-200X software by selecting the shortcut the installer
placed on your desktop.
Step 7:
Establish
Communication
with the LISST-
200X
The LISST-200X does not have an internal battery. Power is supplied
to the instrument via a battery housing or USB cable. Please note that
the LISST-200X USB cable has a USB-to-serial convertor and special
power supply that converts the +5V to +11V to run the instrument built
into cable. When using this cable no other power source is required.
Power can also be provided by the Small and Large External Battery
Housings or another external power source such as a CTD. When
using an external battery the serial communication passes through the
battery housing. However, the power from the USB is not used power
the instrument. Power will be drawn from the battery only.
The LISST-200X software will automatically detect and connect to a
LISST-200X instrument if it is connected to the computer.
If an instrument is found, it will display ‘Connected’ in the lower left
corner.

LISST-200X Introduction & Quick Start 12 LISST-200X User’s Manual
If your instrument is connected to the computer, but not found by the
software, click on the ‘No Instrument Connected’ message to see list
of options. Click on the ‘Communication Help’ button for
troubleshooting help.
Step 8: Open
Terminal
window
The LISST-200X software has a terminal window that allows the user
to communicate directly with the instrument using a set of commands.
To open the Terminal window click on the connected instrument
message in the lower left, then click on the wrench icon and select
‘Open Terminal’
A command can be typed into the box in the lower section of the
window. When the Enter key is pressed the command will be sent to
the instrument. A list of the commands that can be sent to the LISST-
200X is displayed when the terminal opens or they can also be found
in the section LISST-200X Command Summary on page 62.