Sequoia LISST-200X User manual

LISST-200X
Particle Size Analyzer
Including
LISST-HAB & LISST-Black
User’s Manual
Version 2.0
October 2020
2700 Richards Road, Suite 107
Bellevue, WA 98005-4200
Tel: [phone] Fax: [phone]
Store Software
USB Card Here

LISST-200X User’s Manual Page iii
©
This document is copyrighted by SEQUOIA SCIENTFIC, INC

LISST-200X User’s Manual Page v
Welcome to the LISST-200X Particle Size Analyzer
Using this manual
This manual is divided into two sections.
I. LISST-200X contains an introduction to the LISST-200X
instrument and the principles of its operation.
II. LISST-200X Operation provides a detailed set of instructions
for using and caring for the instrument.
Technical assistance
For technical assistance please contact your local Distributor or
Sequoia. Please be sure to include the instrument serial number
with any correspondence.
IMPORTANT: Please read Appendix I: Technical
Assistance & Troubleshooting BEFORE you call or
email.
Sequoia Scientific, Inc. contact information:
Telephone: [phone]
Email: [email protected]

LISST-200X User’s Manual Table of Contents Page vii
Table of Contents
I. LISST-200X INTRODUCTION AND TUTORIAL....................................................................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....................................................................................28
D. STEP BY STEP PROCEDURES...............................................................................................29
1. Installing LISST-200X Software....................................................................................29
2. Establishing Communication with the LISST-200X......................................................30
3. Saving and Evaluating Clean Water Backgrounds.......................................................31
4. Configuring Data Collection..........................................................................................34
5. Using the Small External Battery Pack.........................................................................39
6. Using the Large External Battery Pack.........................................................................42
7. Offloading and Deleting Data Files from Internal Memory ...........................................46
8. Processing a Single Raw Data File ..............................................................................47
9. Batch Processing Multiple Raw Data Files...................................................................49
10. View Processed Data File ........................................................................................51
11. Data Quality Control.................................................................................................52
12.Simple Real-Time Data Processing .........................................................................54
13. Collecting Data from an External Analog Sensor.....................................................56
14. Configuring the LISST-200X as a Sensor for a CTD ...............................................57
E. INSTRUMENT COMMUNICATION.............................................................................................58
F. LISST-200X COMMAND SUMMARY......................................................................................62
G. LISST-200X COMMAND DETAILS.........................................................................................64
1. Display Commands.......................................................................................................64
2. Setup Commands.........................................................................................................68
3. Acquisition/Action commands.......................................................................................75
H. PERFORMANCE OPTIMIZATION .............................................................................................78
I. INSTRUMENT MOUNTING,DEPLOYMENT ORIENTATION,STORAGE AND MAINTENANCE.............81
APPENDIX A: TECHNICAL SPECIFICATIONS...........................................................................84
APPENDIX B: PARTICLE SIZE BINS ..........................................................................................86
APPENDIX C: DATA FILE FORMATS .........................................................................................87
APPENDIX D: PROCESSING DATA FILES USING MATLAB....................................................91
APPENDIX E: CONNECTORS .....................................................................................................93
APPENDIX G: SPHERICAL AND RANDOM PARTICLE SHAPE MODELS...............................98
APPENDIX H: LISST-BLACK & LISST-HAB...............................................................................99
APPENDIX I: TECHNICAL ASSISTANCE & TROUBLESHOOTING.......................................102
WARRANTY ................................................................................................................................104
REVISION HISTORY...................................................................................................................107

LISST-200X User’s Manual Table of Contents Page viii

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 1
I. LISST-200X Introduction and Tutorial
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). That is the essence of this method. In
order that you appreciate the importance of some steps in operation of
the LISST-200X, we recommend reading the rest of this chapter.
The measurement of scattering at multiple angles is done with a
collimated beam illuminating particles in 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). Thus, 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 –conversion 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 User’s Manual LISST-200X Introduction and Tutorial Page 2
Clean Water
Backgrounds
and Background
QC
Imperfections, such as micro-scratches on glass windows and lenses,
also scatter laser light. This is measured and stored; it constitutes a
Background (formerly termed zscat, as in scattering by zero
concentration of scatterers). This background is subtracted from the
total signal seen by ring detectors. It is also helpful in determining if the
instrument is properly aligned, and if all optics are clean and
unscratched. A factory background acts as a reference to compare
with, to identify degradation in laser output or fouling of optical
surfaces. The LISST-200X stores its factory background data in its
memory, as well as the user’s acquired background data.
The LISST-200X incorporates a major advance over our previous
LISST-100X. This is the automatic quality control of the background
data (QC). During background acquisition, after grabbing a group of
scans of all detectors, their means and variances are computed.
Comparing with the on-board factory background, these are used to
alert the user of possibilities such as laser degradation, possible 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. If no warnings are generated,
the background passes QC and the user has the option to save it, or
repeat.
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 daylight at shallow depths can still be significant.
The LISST-200X now can measure the ambient light independently of
scattered light, and subtract it to completely remove its effects. (Note
that this function requires firmware version 1.4 or later, introduced in
May, 2017). See section H for more about ambient light rejection
(ALR).
Quick Estimates
of Particle
Concentration
and Mean Size
The process of inverting laser diffraction data to produce PSD requires
too much computation to execute in real time within the instrument. But
the LISST-200X does provide real-time estimates of the total particle
volume concentration and mean particle size. These are approximate
quantities, 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 57.)

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 3
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%. In such
clear waters, the SMD can become erratic. [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].
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. Only in exceptional circumstances, the spherical model
is appropriate.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 4
B. LISST-200X General Description
Instrument
Description
The LISST-200X is capable of autonomous operation when used with
external battery packs. Windows software (compatible with Windows
XP through Windows 10) is provided to program the instrument for a
specific sampling schedule. 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. An
Auxiliary port is available for that can be configured for recording data
from an external device such as a turbidity or fluorometer or output
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 93.
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 86 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 data logger. All these components
are inside the black-anodized pressure housing.
The LISST-200X does not have internal batteries and therefore
should not need to be opened.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 5
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 range1. The stainless steel fitting on the
Connector endcap is used for testing this sensor, and keeps
contamination such as salt and sediment out of the pressure sensor.
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 is also equipped with an external Auxiliary port which
is available via a 6-pin connector in the endcap. This port can be
configured in different ways by the user.
The Standard Configuration has one analog input and two digital
inputs. The analog voltage on this input is recorded with the size
distribution data. The digital inputs can be used to start and stop the
instrument.
The Analog Input Configuration has two analog inputs and switched
power which can be used to power the external sensor. Both analog
voltages are stored with every size distribution.
The Analog Output Configuration allows the Mean Size and Total
Concentration information to be output as analog voltages. The 6-pin
connector is wired to match the SeaBird CTD Auxiliary Input. This
allow the LISST-200X to obtain power from the CTD and output the
mean size and total concentration in real time to the CTD while the
detailed size distribution data is stored internally for later downloading.
The Auxiliary port can be reconfigured by the user by moving
mechanical jumpers on the main circuit board inside the instrument.
Contact Sequoia Scientific for instructions on how to access the jumper
on the circuit board.
1
A gauge pressure sensor is calibrated to measure the pressure relative to a given atmospheric pressure, as opposed to
an absolute pressure sensor, which measures pressure relative to a vacuum. The pressure sensor on the LISST-200X
will read 0 at atmospheric pressure.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 6
Battery Life
The LISST-200X does not contain internal batteries (except a small
battery to maintain the real-time clock), but can be powered from
multiple sources including a USB computer cable, Small or Large
Battery Packs (provided with the instrument) or an external instrument
such as a CTD.
The standard Small Battery Pack supplied with the LISST-200X uses
two NiMH rechargeable D-cell batteries and will provide about 12 hours
of continuous sampling.
The Large Battery Pack contains 16 standard alkaline D-cells. For
profiling applications, where the instrument is sampling continuously,
the Large Battery Pack has about 200 hours of sampling time or 200
days of stand-by. Powering down the instrument between samples can
greatly extend the deployment times. An Excel spreadsheet that can
estimate the battery consumption is included with the software on the
Ship Disk you received with your instrument. The spreadsheet can also
be downloaded from www.sequoiasci.com/product/lisst-200x, click
Library, then Downloads, then LISST-200X.
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 LISST-200X Introduction and Tutorial Page 7
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 Pack (without batteries),
•Larger Battery Pack with alkaline batteries installed,
•LISST-200X-to-Battery Pack cable,
•NiMH batteries and charger.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 8
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.
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 for a full description of the wiring of the underwater
connectors and mating cables.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 9
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.
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.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 10
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
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 the Step-by-Step guide on page 29 of the User’s Manual.
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.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 11
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.
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.

LISST-200X User’s Manual LISST-200X Introduction and Tutorial Page 12
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 pack 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
Packs or another external power source such as a CTD. When using
an external battery the serial communication passes through the
battery pack. 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.
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.