Sequoia LISST-100X User manual

User’s Manual
Version 4.65
2700 Richards Road, Suite 107
Bellevue, WA 98005-4200
Tel: [phone] Fax: [phone]
LISST-100X
Particle Size Analyzer

©This document is copyrighted by SEQUOIA SCIENTFIC, INC.

LISST – 100 User’s Guide
Welcome to the LISST-100X Particle Size Analyzer
Using this manual
This manual is divided into two sections.
Section One contains an introduction to the LISST- 100
instrument and the principles of its operation.
Section Two provides a detailed set of instructions for using
and caring for the instrument.
Instrument specifications
For a listing of instrument-specific constants, as used in the
software for data processing, refer to Appendix A.
Technical assistance
For technical assistance please contact your local Distributor or
a Sequoia Technical Service Representative listed below.
Please be sure to include the instrument serial number with any
correspondence.
Factory Technical Service Representatives
Chuck Pottsmith
[email protected]; [phone] ext.107
Doug Keir
[email protected]; [phone] ext.104

1 LISST – 100X User’s Guide
Table of Contents
SECTION 1: INTRODUCTION TO THE LISST-100X .............................................................................2
INTRODUCTION............................................................................................................................................2
GENERAL DESCRIPTION...............................................................................................................................5
SECTION 2: OPERATION........................................................................................................................8
GETTING STARTED ......................................................................................................................................9
STEP BY STEP PROCEDURES.......................................................................................................................23
Step by Step Procedure: Record and Store Background Scatterfile...................................................24
Step by Step Procedure: Offloading/Deleting Data Files...................................................................26
Step by Step Procedure: Processing raw data....................................................................................28
Step by Step Procedure: View processed datafile................................................................................32
Step by Step Procedure: Real-time data processing...........................................................................35
Step by Step Procedure: Configuring data collection ........................................................................38
INSTRUMENT COMMUNICATION ................................................................................................................43
LISST-100X COMMAND SUMMARY .........................................................................................................47
LISST-100X COMMAND DETAILS ............................................................................................................48
PERFORMANCE OPTIMIZATION ..................................................................................................................54
INSTRUMENT MOUNTING...........................................................................................................................57
INSTRUMENT STORAGE &MAINTENANCE.................................................................................................58
TECHNICAL SPECIFICATIONS .....................................................................................................................62
APPENDIX A: INSTRUMENT SPECIFIC DOCUMENTATION...........................................................63
APPENDIX B: DATA STORAGE FORMAT AND SIZE RANGES.........................................................64
APPENDIX C: CONNECTOR PINOUTS FOR LISST-100X...................................................................66
APPENDIX D: LISST-SOP SOFTWARE BUTTON DESCRIPTION....................................................68
APPENDIX E: SOFTWARE UPGRADE INSTALLATION PROCEDURE...........................................69
APPENDIX F: HORZONTAL CHAMBER INSTALLATION PROCEDURE........................................72
APPENDIX G: BIOBLOCK INSTALLATION AND USE........................................................................73
WARRANTY...............................................................................................................................................77

LISST – 100 User’s Guide 2
Section 1: Introduction to the LISST-100X
Introduction
Principle of
Operation The product name LISST is derived from the term that describes
its operation: Laser In-Situ Scattering and Transmissometry.
LISST is a Trademark of Sequoia Scientific, Inc.
The LISST-100X instrument uses the technique of laser
diffraction to obtain particle size-distribution (PSD), also called
volume distribution in this manual. This section describes the
principle of operation of your instrument.
A collimated laser
beam enters water,
light is scattered by
particles and sensed
by a multi-ring
detector behind a
receiving lens. A
photodiode placed
behind a centered
hole measures
optical transmission
The laser diffraction method for sizing particles was invented in
the 1970’s and rapidly became the most widely used optical
method for determining size distribution for the simple reason
that for laser diffraction, the composition or refractive index of
the particles is not important. This method determines size
distribution of an ensemble of particles, as opposed to counting
type devices that size one particle at a time. The reason that laser
diffraction is unaffected by composition of particles is that the
scattering of laser light is observed at multiple, small forward
angles. At these small angles, light scattering is determined
almost entirely by light diffracted by the particle. The light
transmitted through the particle makes only a weak contribution
to the measured scattering. Since the light transmitted through the
particle would experience the composition of the particle, i.e. its
refractive index, and since it makes only a weak contribution
to the observed scattering, the method of laser diffraction is
mostly independent of particle composition. In the aquatic
sciences, particle refractive index is poorly known. Thus, except
for shape effects, laser diffraction offers an excellent method for
size-distribution estimation. Shape effects are a matter of
continuing research and no definite generalized guidelines are
available to account for them by any method. Consequently, laser
diffraction methods deliver the equivalent-spheres size
distribution. By calibrating for concentration with ISO standard
natural particles, shape effects are empirically included.
Continued on the next page...

3 LISST – 100X User’s Guide
The LISST-100X records the scattering intensity over a range of small angles using a specially constructed multi-ring detector
shown in the graphic above. This measurement is also known to
optical scientists as the volume scattering function and can be
used as such for studies of underwater image propagation and
beam spread. A growing number of publications of measure-
ments using the LISST-100X instrument is available on our
website: http:www.sequoiasci.com.
The conversion of the multi-angle scattering to size distribution
involves a mathematical inversion. In this step, a size-
distribution is found that would produce multi-angle scattering
that fits the observation. There exists a vast literature on the
subject of this inversion. For the stout-hearted user interested in
learning all about it, we recommend the most germane study of
the subject:
"Optimal scaling of the inverse Fraunhofer diffraction
particle sizing problem: The linear system produced by
quadrature," by E. D. Hirleman, Particle Characterization,
4, 128-133, 1987.
The main conclusions are that the information content of the data
is most stably retrieved by use of ring-type detectors, with each
ring measuring the scattering over a sub-range of angles, and that
the resolution is limited to relatively few size classes depending
on the noise in the data. For example, for the dynamic range in
scattering angles of 200:1 that is built into the LISST systems,
typically only 12-14 truly independent size classes can be
resolved.
Simpler descriptions of principles and practice are offered in a
separate study by Agrawal et al., 19911. A more up to date
description of the technology and its application is provided by
Agrawal & Pottsmith, 20002.
We explain the inversion process as follows: Let E be the 32-
element data vector that contains the angular scattering energy
sensed by the 32 silicon rings. It is related to the volume
distribution3via
E = K NV
where K is the scattering property kernel matrix and NVis the
volume distribution.
1Agrawal, Y.C., I.N. McCave, and J.B. Riley, 1991: "Laser diffraction size analysis," in Principles, methods and applications of
particle size analysis, J.P.M. Syvitski, editor, Cambridge University Press, pp. 119-128.
2Agrawal, Y. C. and H. C. Pottsmith, 2000: Instruments for Particle Size and Settling Velocity Observations in Sediment Transport,
Marine Geology, 168, pp 89-114.

LISST – 100 User’s Guide 4
The volume distribution is obtained by inverting the above
equation. To test whether the estimated solution is a good one,
one may compute the prediction of a scattered energy estimate Ee
as
E
e= K Ne
If the measurements E are consistent with Ee , the estimates of Ne
can be considered good. Included with the LISST-100X
instrument, we have provided software that obtains the inverted
volume distribution NV. We have also provided the matrix K for
your instrument (in ASCII and MATLAB®formats) in order for
you to test your results.
3The volume distribution is related to the number distribution via NV= a3n(a). It represents the volume concentration of particles
of particles in the size range ato a+ da. The results from the LISST instruments provide the volume concentration of particles in
each of 32 size classes. The size classes are log-spaced from the range 1.25-250 microns (Type-B instruments), 2.5-500 (Type-C),
or 7.5-1500 microns (Type-D, LISST-FLOC). See Appendix B for further details.

5 LISST – 100X User’s Guide
General Description
The LISST-100X 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, a data storage and scheduling
computer, and a battery system.
The instrument is capable of autonomous operation. For such
operation, software is provided to program the instrument for a
specific sampling schedule. The primary measurements delivered
by the LISST-100X are the small-angle scattering properties of
particles in water, the laser optical transmissivity, depth, and
temperature. An auxiliary Analog port is available for recording
data from an external input.
After recovery of the instrument, small-angle scattering data are
off-loaded from the instrument and subsequently inverted
mathematically on a PC to produce the particle size distribution.
The inversion function is included in the software.
The principal measurement—angular scattering distribution— is
obtained over 32 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 0.0017 to 0.34 radians (Type-B), 0.00085-
0.17 (Type-C), or 0.00028-0.053 radians (Type-D, or LISST-
FLOC) . This angular range corresponds, respectively, to size
rangesL 1.2 to 250 microns (Type-B), 2.5-500 (Type-C) and 7.5-
1500 microns (Type-D, or LISST-FLOC).
General layout This self-contained instrument consists of the following parts: a
solid-state laser operating at 670nm wavelength and fiber-
optically connected to a laser beam collimating system, a beam
manipulation and orienting system, a scattered-light receiving
lens, the specially designed 32-ring detector, preamplifier
electronics, a ring-selecting multiplexer circuitry, and a data
logger.
Depth and
Temperature In addition to measuring the particle size and concentration, the
LISST-100X also has built-in Depth and Temperature sensors.
The Depth sensor is a 500 psi strain gauge sensor. The stainless
steel fitting on the Connector endcap is used for testing this
sensor. It is not required for normal operation. However,when not
used for testing, this fitting helps keep contamination out of the
pressure sensor. The temperature is measured using a high
precision thermistor imbedded into the Connector end cap. Both
values are stored automatically in the standard-format LISST-
100X datafile.

LISST – 100 User’s Guide 6
External I/O Ports The LISST-100X is also equipped with an external ANALOG IN
port for recording the output of one other analog instrument.
Additionally, 2 DIGITAL I/O ports are provided for
communicating with up to two instruments. The I/O ports can be
used for synchronization of the LISST-100X with two other
instruments; e.g., the LISST-100X may provide a timing pulse to
a CTD, or it may provide a 'start sample' pulse to another LISST-
100X. The same ports can be used to receive similar commands.
Contact Sequoia Scientific for more information on interfacing
the LISST-100X with other instruments. These ports are available
on the 6-pin underwater connector on the Connector Endcap.
Appendix C shows the connector pinouts. The instrument can be
configured to use the Digital I/O ports as a trigger to start and
stop sampling.
Battery Life
The primary power source for the LISST-100X is a custom
alkaline D-cell battery-pack. The pack outputs +9 volts. It has a
room-temperature capacity of 42 A-hr. When the instrument is in
stand-by mode, (i.e., displaying the L100X> prompt) the current
drain is 8.5 mA. In Low Power Sleep mode the current drain
drops to 120 µA. For profiling applications, where the
instrument is sampling continuously, the battery pack has about
60 hours of “On” time. Powering down the instrument between
samples can greatly extend the deployment times. An EXCEL
spreadsheet is included with the software that can estimate the
battery consumption
For laboratory or tethered usage, a connector is provided on the
endcap to draw power from an external source. The voltages
required from the external power supply are +9. 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.
When not in use, use the Low Power Sleep mode of
the instrument to reduce battery drain to about
10μA. This can be done from the provided
software.

7 LISST – 100X User’s Guide
Auxiliary
Equipment The instrument is shipped pre-aligned and tested. A 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 are supplied so
that a user need only provide a PC.
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.
For laboratory testing an optional Small Volume Full Path Mixing
Chamber is available. This chamber mounts to the optics of the
LISST-100X and seals around the windows of the instrument.
The sample can then be added to the chamber and the built-in
mixer will keep the sample mixed with the measurements are
being made. The picture below shows the chamber being installed
onto the LISST-100X.

LISST – 100 User’s Guide 8
Section 2: Operation
Section
Organization
General
Precautions
Section 2 is divided in to two main sections. The first section is
the Getting Started section. This section will walk the user
through using the instrument from opening the shipping case
through processing downloaded data. Reading the Getting
Started section will give most users enough information to
starting using the instrument. Following the Getting Started
section are detailed instructions for performing various
procedures
LISST-100X is a sensitive optical instrument. Please handle it
gently. Critical alignments may be disturbed if the instrument is
subjected to shock or rough handling. Evidence of shock/rough
handling will void the warranty. Whenever in transit, store the
instrument in the provided padded shipping case.
WARNING
The LISST-100X uses a laser diode emitting a maximum of 1 mW
of visible (red) light at a wavelength of 670nm. the laser beam
under normal circumstances is not a threat. However, if objects
are placed in the path of the laser beam, the light could be reflected
into the eye causing permanent damage.
.

9 LISST – 100X User’s Guide
Getting Started
Contents of
shipping case
Step 1: Remove
Instrument from
shipping case.
This section is designed to give the user a quick introduction to the
operating procedures for the LISST-100X. It gives step by step
instructions to unpack, load software, and acquire data in the lab.
Following the introduction are details on each step of the process.
Let’s assume that you are opening the LISST-100X shipping cases for
the first time. Inside you will find the following: User’s Manual with
software disk, LISST-100X instrument, Plastic Instrument stands, Small
Volume Horizontal Test Chamber, Communications cable, External
Power cable, and Allen wrench set.
Start by removing the white plastic instrument stands and set them on a
flat working surface. Remove the LISST-100X from the case and set it
on the stands. The LISST-100X has two distinct ends that we will refer
to as the Optics endcap and the Connector endcap. The connector
endcap has three underwater connectors that are used for communication.
external power, and connecting to optional accessories or instruments.
The battery pack is attached to the inside of this endcap. The optics
endcap contains the optical windows that the laser beam passes through
to make a measurement. The internal optics and electronics are mounted
to the inside of this endcap.
Step 2: Check for
clean windows At this time let’s check the optical windows to make sure that they are
clean. There are two windows. The Receive window is mounted in the
center of the optics endcap. Transmit window is located in the Crossbar
suspended above the endcap. 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 water and then by wiping them with a soft cloth and alcohol.
Stronger solvents, such as acetone, can be used if necessary but is not
recommended as a general practice. Liquid dish soap can also be used. In
general, do not use any abrasive cleaners or wipes. Treat the windows as
you would an expensive camera lens.
Step 3: Attach the
Communications
Cable
Remove the Communications cable from the shipping crate. It is the
cable with the 9-pin DB-9 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.
The Communication connector is the only 5-pin connector. If the unit
is rotated so that the metal zinc anode is located at the top (or North),
the Communications connector will be on the left (or West). After
removing the cap install the cable making sure that the proper
alignment is maintained.
Step 4: Install the
Horizontal test Remove the Small Volume Horizontal test chamber from the shipping
case if not already installed on to the instrument. Attach the flexible

LISST – 100 User’s Guide 10
chamber
tubing and tubing stop clamp. This chamber is designed to slip
between the optical windows of the instrument such that the optic can
be submerged for testing or calibration. For more information on
installing the see Appendix F. We can now fill the chamber with clean
filtered water. We use 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.
Step 5: Install the
provided software At this point instrument is ready to go. Let’s install the software that
is required for operation of the instrument. A software disk is
included with each instrument. In addition to the communication and
processing program the disk also contains calibration files specific for
your instrument. Follow the installation instructions in the
README.TXT file on the disk to install the software.
Step 6: Start
LISST_SOP
program
Start the LISST-SOP software by selecting it from the Start menu.
The name LISST-SOP refers to the Standard Operating Procedure
functionality of the program. Users with experience on previous
versions of the LISST-100 software may find the Appendix E, What’s
New in Version 4.XX a good introduction to the software. Appendix
D has a table describing the functions of each button. It is highly
recommend that existing users who are upgrading to Version 4.60
from earlier versions (Versions 3.xx) of the LISST software read
Appendix F before continuing. There are a number of steps that must
be performed before the software will function correctly with older
instruments.
Step 7: Wake up
instrument from
Sleep mode
The instrument is shipped in a low power Sleep mode to conserve
battery power. To wake up the instrument select Wake Up LISST
from the LISST menu. A dialog box will appear counting down the
maximum time required for the instrument to wake up. The
instrument sleeps for 30 seconds, wakes up for 1 second to look for a
wake up command and then goes back to sleep. Therefore the wait
could be as long as 32 seconds for the LISST-100X. Upon wake up
the instrument status will be displayed. If the cable connections are
not correct or if the battery is not installed a warning message will
appear after the time expires. The serial port settings can be checked
by selecting Serial Port Settings from the Communication menu. The
default settings are COM1, 9600 baud, 8 data bits, No parity, 1 stop
bit, and no protocol.

11 LISST – 100X User’s Guide
Step 8: Open
Terminal window
The LISST-SOP has a terminal window that allows the user to
communicate directly with the instrument. To open the Terminal
window select Terminal Window from the Communications window or
select the button form the tool bar. A window similar to the one
shown below will appear.
Commands can be typed into the box in the lower section of the
window. When the Enter key or the Send button is pressed the
command will be sent to the instrument. The Start button sends a GO
command to the instrument to start the instrument sampling using the
current settings. The STOP button sends a CTRL-C to stop the
sampling and to turn off the main power.
Pressing enter should bring up an L100X> prompt.
If the instrument is still in the Low Power Sleep Mode it will print ZZZ
to the screen every 30 seconds. To wake the instrument from the
Terminal window, press the Stop button immediately after the ZZZ is
displayed. The instrument will only respond to the Stop button for 1
second after the ZZZ is displayed. After the 1 second the instrument is
in a low power mode and will not respond to commands for another 30
seconds.

LISST – 100 User’s Guide 12
Step 9: Intro to the
new Datalogger
The datalogger inside the LISST-100X has recently been upgraded. It
is different from earlier versions of the LISST-100. New instruments
using the new datalogger have been given the name LISST-100X. Units
using the previous version datalogger will be called LISST-100. The
new datalogger of the LISST-100X uses removable Compact Flash
cards. Compact Flash Cards are available with up to 1Gb of memory.
The LISST-100X comes standard with 128Mb. The Compact Flash
Cards can be removed. By using a PCMCIA adapter or USB card
reader the data files can be directly transferred to the PC. The standard
procedure is to offload the files using the LISST-SOP software at 115K
baud.
The LISST-100X now has standard two-letter commands that can be
used for interfacing the instrument with other dataloggers and sensors.
The commands are similar to the commands used with the LISST-25X
instrument. A complete description of the commands is shown in the
LISST-100X Command Summary section.
Step 10: Acquiring
Background
Scattering
A new feature of the LISST-SOP is the ability to acquire background
scattering in real-time. The background scattering measurement is
critical to good instrument performance. It is especially critical for
clean water applications where the optical transmission is greater than
80% over the 5cm path. The background scattering will also check the
overall health of the instrument. It will verify that all of the systems
are functioning and that the optics are still in alignment. The current
background will be acquired and displayed relative to the factory
background scattering for the instrument. The image below shows an
example of this display. It is opened by either selecting Collect
Background Scatter Data from the LISST menu or by pressing the
button on the toolbar. After selecting the factory background scatter
file to use for comparison the window will display.
When the BEGIN Collect button is pressed 20 samples will be
displayed to the screen as they are acquired. After all 20 are collected

13 LISST – 100X User’s Guide
the average will be displayed. If the values are acceptable the values
can be saved to a file. Enter the filename in the box and press the
Accept and Save button.
If there is a problem with the instrument or if the water or windows are
not clean, error messages will be displayed. Dirty water or windows
will generally cause higher values across the middle rings. Large
bubbles or particles in the water can cause higher values on the inner
rings or left hand side of the display. High values on the inner rings
combined with a lower Laser power value can also be an indication of
optical misalignment.
Step 11:
Configuring
Instrument for
Deployment
The heart and soul of the new LISST-SOP software is the Operating
Modes window. This window is used to set all of the deployment
parameters. To open the window, choose Operating Modes from the
LISST menu or press the button on the tool bar. A window similar
to the one shown below will appear.
The window has four tabs, Instrument Status, Operating Mode, Start
Condition, and Stop Condition. The Instrument Status page gives
information about the current instrument. It also allows previously
saved instrument configuration files to be loaded on to the instrument.
The ability to save the current settings to a file is also available. The
Summary window shows the current deployment configuration.
Step 12: Setting
Operating Mode By selecting the Operating Mode Tab at the top of the main window
the screen below appears. This screen is used to set the type of
sampling; RealTime, Burst, or Continuous. You can also select the

LISST – 100 User’s Guide 14
samples per average and sample rates on this screen.
The RealTime mode is used for real-time size distribution displays.
This mode sends the raw data to the LISST-SOP software for
conversion to Size Distribution and displaying on the screen. No data is
saved in the datafile.
The Burst and Continuous modes are used to save data in the on-board
datafile. The icons next to the various values give a better
understanding of their meaning. The software automatically checks the
values entered to make sure that there is no conflict. For example,
when a Measurements per Average value is entered, the minimum
sample interval is computed. If this value is less than the minimum
permitted the value will be changed to the minimum and the text will
turn red. A similar test is done on the Burst Interval setting.
For this example let’s set the instrument to sample in the Continuous
mode at a 1 Hz rate with 10 measurements per average.
Step 13: Setting
Start Conditions After selecting the Operating mode the start and stop conditions can be
selected. Choose the Start Condition tab at the top of the window.
The Start Condition window, shown below, is used to select the mode
in which sampling will be started.

15 LISST – 100X User’s Guide
There are five options: Depth, Time, External Mechanical Switch,
External Digital Input, and Time Delay. Select the mode by clicking
on the button next to the its label. Select the correct parameters as
required. For this example let’s select the External Mechanical Switch
Start Condition.
Step 14: Setting
Stop Conditions Similarly the Stop conditions can also be selected. Click on the Stop
Condition Tab to open the Stop Condition window. The available stop
conditions are: Depth, Time. External Mechanical Switch, External
Digital Input, Fixed number of samples, and Maximum Memory or
Low Battery.

LISST – 100 User’s Guide 16
For this example, choose the External Mechanical Switch as the Stop
condition.
After selecting the Stop Conditions return to the Instrument Status page
by clicking on the Instrument Status Tab.
Step 15: Saving
the settings for
future use
Once the settings have been sent to the instrument the Instrument Status
Page will display the summary of the settings that have been selected.
These setting can be saved for later use by selecting the Save Summary
to LOP. A file name will be prompted for. The file will be given an
LOP extension which will identify it as a LISST Operating Procedure
File. Comments can be entered before saving in the box below the
summary. Previously saved LOP file can be opened using the Browse
button.
Press the Apply button to configure the instrument. This will cause the
settings to be transmitted to the instrument. The configuration will take
about 30 seconds. Once the configuration is completed we can return to
the Instrument Status page to see the summary of the settings and save
them for future use if desired. Press the OK button to complete the
configuration. A prompt will ask if we would like to open the Terminal
window to start the instrument. Choose OK
Step 16: Starting
the program The instrument is now configured for deployment, however, it is not yet
running. In order for the instrument to respond to the correct Start
Condition the program must be started.
The configuration of the instrument can be checked by selecting Query
Instrument from the LISST menu or by choosing the button from the
tool bar. A window will appear showing the current status and
configuration. To start the program, press the Start button in the lower
right section of the Terminal window. The program will start and display
text to the screen as it is running. Depending upon the Start Conditions,
text will be displayed approximately every 30 seconds. At this point the
user will know that the instrument is running and is ready to be deployed.
For our example it will be displaying a message that reads “Waiting for
Mechanical Switch ON signal”
Step 17: Collecting
Data
When the start conditions are met the instrument will start sampling. The
green LED on the connector endcap will illuminate each time a sample is
acquired.
For our example we can move the white plastic lever on the endcap to the
“1“ position. Sampling will start. If the Terminal window is still open
text will be displayed as the instrument acquires data. Data collection
will continue until the Stop Conditions are met. In our case, until the
switch lever is returned to the “0” position.
If the Start and Stop Conditions are set to Depth, External Mechanical
Switch, or External Digital Input the program will return to checking for