Dakota UMX-2 User Manual
OPERATION MANUAL
DAKOTA ULTRASONICS
UUMMXX--22
Underwater Material & Coating Thickness Gauge
P/N P-185-0004 Rev 1.0, May 2010
UMX-2 Underwater Material & Coating Thickness Gauge
CHAPTER ONE INTRODUCTION - CARE & WARRANTY................................1
CHAPTER TWO QUICK STARTUP GUIDE........................................................4
CHAPTER THREE OVERVIEW...........................................................................7
CHAPTER FOUR MENU & CONNECTOR REFERENCE................................11
CHAPTER FIVE PRINCIPALS OF ULTRASONIC ME ASUREMENT ...............18
CHAPTER SIX SELECTIN G THE MEASUREMENT MO DE.............................22
CHAPTER SEVEN MAKING MEASUREMENTS ..............................................24
CHAPTER EIGHT ADDITIONAL FEATURES & OPTI ONS...............................32
CHAPTER NINE THRU PA INT MEASUREMENT TECHNIQUE ......................37
CHAPTER TEN PULSE-ECHO COATING & COATING TECHNIQUES..........39
CHAPTER ELEV EN DATA STORAGE – SETUP, EDIT, & VIEW FILES.........43
CHAPTER TWELVE SETUPS – CREATE, STORE, EDIT, & UPLOAD...........58
CHAPTER THIRTEEN UPG RADING THE FIRMWARE...................................65
APPENDIX A - VELOCITY TABLE .....................................................................70
CHAPTER ONE
INTRODUCTION - CARE & WARRANTY
The Dakota Ultrasonics model UMX-2 is an underwater ultrasonic thickness gauge
that measures with extreme versatility. It has the ability to simultaneously measure
coatings and material thicknesses while maintaining the ability to locate pits, flaws
and defects in the material. It can also use a combination of dual and single element
transducers, depending on the application requirements. Based on the same
operating principles as SONAR, the UMX-2 is capable of measuring the thickness of
various materials with accuracy as high as ± 0.001 inches, or ± 0.01 millimeters. The
principle advantage of ultrasonic measurement over traditional methods is that
ultrasonic measurements can be performed with access to only one side of the
material being measured.
Dakota Ultrasonics maintains a customer support resource in order to assist users
with questions or difficulties not covered in this manual. Customer support may be
reached at any of the following:
Dakota Ultrasonics Corporation
1500 Green Hills Road, #107
Scotts Valley, CA 95066 USA
Telephone: (831) 431-9722
Facsimile: (831) 431-9723
http://www.dakotaultrasonics.com
1.1 Care & Maintenance
The UMX-2 housing is made of a clear PVC material that is very durable and well
suited for this application given the following conditions are followed:
• Keep the UMX-2 out of direct sunlight as much as possible to avoid any
potential ‘crazing’ or stress cracking, as well as discoloration.
• Protect the housing from impact.
• Submerge or rinse the enclosure and transducers in fresh water following use.
• Warning: Do not exceed the depth limitation of 1000 ft. Failure adhere to this
warning may result in leakage, potential implosion and serious injury.
The housing is sealed by o-rings, one on each end cap, which require meticulous
care. In order to maintain a watertight seal, the o-rings and their mating surfaces
must be clean, free of foreign material, and lubricated with silicone grease.
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UMX-2 Underwater Material & Coating Thickness Gauge
The following procedure must be performed on the end cap o-rings before
each use:
1. Clean all old silicone grease from o-rings and mating surfaces using paper towels.
2. Inspect o-rings for foreign material (sand, seaweed, hair, etc.), cracks, cuts, soft
spots, or deformities. Replace o-ring if damaged. Inspect mating surfaces for
scratches, rough spots, dents, or cracks.
3. Apply thin, even coat of silicone grease to o-rings on each end cap using finger to
spread evenly . Inspect to be sure the o-ring has been properly fitted, and screw
the end cap back in place, until it has a nice snug fit.
1.2 Warranty
The UMX-2 is protected by a 3 year limited liability:
1. The manufacturer inspects and tests every UMX-2 for watertight integrity
before it is delivered.
2. The manufacturer will repair or replace at the manufacturer's option any
housing that proves to be defective in const ruction or materials within three
year of date of delivery.
3. The Manufacturer will repair or replace at the manufacturer’s option any
transducer that proves to be defective in construction or materials within 90
days of date of delivery, evaluated up to 1 years time.
4. The manufacturer is not liable for damage to equipment caused by leakage of
water into the housing, nor is the manufacturer liable for loss of data or income
there from as may result from such leakage. The manufacturer is not liable for
any accidents during which this housing was in use.
5. This warranty is void in the event of negligent handling of the housing
including, but not limited to, dropping the housing, modifications to the housing
by other than the manufacturer, improper care of the sealing components, and
exceeding the specified depth limitation of 1000 feet.
6. There is no express or implied warranty, nor warranty of merchantability,
except as stated by the manufacturer above.
7. The buyer understands that, because of the nature of this product, he/she
uses the housing at his/her own risk and agrees to hold the manufacturer
harmless, except as stated above.
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1.3 Disclaimer
Applies to dual element transducers: Inherent in ultrasonic thickness measurement
is the possibility that the instrument will use the second rather than the first echo from
the back surface of the material being measured. This may result in a thickness
reading that is TWICE what it should be. Responsibility for proper use of the
instrument and recognition of this phenomenon rest solely with the user of the
instrument. Other errors may occur from measuring coated materials where the
coating is insufficiently bonded to the material surface. Irregular and inaccurate
readings may result. Again, the user is responsible for proper use and interpretation
of the measurements acquired.
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UMX-2 Single Element Menu Structure & Factory Configuration
CHAPTER TWO
QUICK STARTUP GUIDE
The UMX-2 is pre-configured at Dakota Ultrasonics with a specific and common
setup. As a result, the gauge should be ready to measure once the transducer has
been connected. Th e UMX-2 can use two different styles of transducers; dual
element and single element membrane. As a result, the gauge will be configured
according to the transducer style purchased, as follows:
2.1 Factory Setup Parameters (Single)
Top Level
STORE DIRECT CLEAR MATL UNITS MODE UMX-2
A 1 NORTH LOC ALU IN E-E-E LT ON
SOUTH STL MM LT OFF
EAST STST LTAUTO
WEST IRON MEMOFF
CIRO UPGRAD
PYC
PLST
PLUR
CUSTOM
2.2 Quick Start (Single Element)
Procedure
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UMX-2 Dual Element Menu Structure & Factory Configuration
1) Referring to the diagram above, be sure the dongle and transducer are
connected as illustrated. Note: in order for the UMX-2 to recognize the
transducer that has been attached, it must be in the proper channel location.
2) Press and release the single button located on the end of the UMX-2. The
displays should illuminate, and led lights will begin flashing.
3) The smaller of the two displays will begin scrolling the current configuration
settings of the UMX-2 in the following order: UMX-2, BATT (LO, ME, HI),
Probe Type (1/2 2S or 5S)…etc. If ‘NO PRB’ is displayed, the dongle has
been plugged into the wrong channel. Press and hold down the button for
approximately 30 seconds, or until the UMX-2 powers off. Repeat steps 1 –
3 until the probe has been identified.
4) The UMX-2 is ready to begin making measurements.
2.3 Factory Setup Parameters (Dual)
Top Level
STORE DIRECT CLEAR ZERO GAIN MATL UNITS MODE UMX-2
A 1 NORTH LOC AUTO VLOW ALU IN P-E LT ON
SOUTH MANUAL LOW STL MM PECT LT OFF
EAST COATIN MED STST E-E LTAUTO
WEST HIGH IRON MEMOFF
VHIGH CIRO UPGRAD
PYC
PLST
PLUR
CUSTOM
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UMX-2 Underwater Material & Coating Thickness Gauge
2.4 Quick Start (Dual Element)
Procedure
1) Attached the transducer to the UMX-2.
2) Press and release the single button located on the end of the UMX-2. The
displays should illuminate, and led lights will begin flashing.
3) The smaller of the two displays will begin scrolling the current configuration
settings of the UMX-2, and an auto zero will be performed.
4) The UMX-2 is ready to begin making measurements.
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CHAPTER THREE
OVERVIEW
Turn the UMX-2 on and off using the switch located on the bottom right corner of the
keypad. When UMX-2 is initially turned on, a UMX-2 logo will be displayed,
accompanied by lots of flashing led lights. The UMX-2 will attempt to ‘auto identify’
the transducer type that is connected, or display ‘NO PRB’ if the transducer cannot
be identified. The following sections outline each scenario. Note: This section is
primarily written as a basic startup guide only.
3.1 UMX- 2 Displays
6 Character, 16 Segment Alpha Numeric Display
The UMX-2 is equipped with two segmented LCD displays that are used for entirely
different purposes. The 6 Character display above, is used for all the menu options
and any text to control the overall operation and functionality of the UMX-2. Since
the UMX-2 has the ability to store measurements, this display is also used to view
and move to specific cell/storage locations in the grid storage structure of the gauge.
Note: The left most ‘comma’ located in the top left corner of th e display, identifies
which sub menu feature option is currently selected, as shown above. In this
example the gain is currently set to medium.
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UMX-2 Underwater Material & Coating Thickness Gauge
4 Digit , 8 Segment LCD Display
The 4 digit display illustrated above, is considered the primary measurement display
of the UMX-2. The following outlines the measurement display: The numeric portion
of the display consists of 4 complete digits preceded by a leading "1", and is used to
display numeric values, as well as occasional simple words, to indicate the status of
various settings. When the UMX-2 is displaying thickness measurements, the
display will hold the last value measured, until a new measurement is made.
These eight vertical bars form the Stability Indicator. When the UMX-2 is idle, only
the left-most bar and the underline will be on. When the gauge is making a
measurement, six or seven of the bars should be on. If fewer than five bars are on,
the UMX-2 is having difficulty achieving a stable measurement, and the thickness
value displayed will most likely be erroneous.
3.2 Single Button Operation
The UMX-2 is controlled using a single button to move around the menu structure
and enable/disable its features. There are 3 basic ‘button press’ sequences available
as follows:
Press & Hold:
Primary function – enter into, or exit out of the menu structure.
When the button is pressed and held down for a specific duration of time, the single
level menu structure will begin scrolling through the to p level of menu items
continuously. If entering into the menu structure, “Enter” will be displayed, followed
by scrolling through the menu items. If exiting the menu items, “Exit” will be
displayed, followed by advancing to the current storage location (i.e. A 1), or
“MEMOFF” if data storage has been disabled by the user. Once either instance has
occurred, the button can be released.
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Press & Release:
Primary function – selection of menu items.
To select a menu item, press and release the button. The sub menu items will begin
scrolling on the display. Finally, to select a sub menu item, press and rel ease again.
Press & Long Hold:
Primary function – manually turn off the UMX-2.
The UMX-2 will automatically shut off after 5 minutes if it hasn’t detected a
measurement. However, to be sure the unit is shut off after use, when the button is
pressed and held down for approximately 10 seconds, “POWER” “OFF” will be
displayed, and the unit will manually turn off . Once the unit turns off, the button can
be released.
It’s really just that simple!
3.3 Gauge Settings
The current settings of the UMX-2 will be displayed on initial power up and every 30
seconds following. This is intended to provide the user with an easy way to confirm
the settings at any time, without having to scroll to the specific menus items
individually. The parameters will be displayed in the order that follows:
Gauge Model:
Battery Status: LO, MED, or HI
Transducer Type Identified: ½ 5, ½ 3.5, ½ 2 S, ½ 5 S
Measurement Mode:
Current Gain Setting: VLOW, LOW, MED, HIGH, VHIGH
Material Type: ALU, STL, STST, IRON, CIRO, PVC, PLST, PLUR, or Custom
UMX-2
P-E, PECT, E-E or TCG
However, if the user is in the menus and viewing the sub menu items, the currently
selected option/featu re can be identified by the “,” (comma) illuminated in the top left
corner of the small display.
3.4 Menu Structure
The UMX-2 has been carefully designed to minimize the overall level of drop down
menu options in an effort to keep the gauge as simple to operate as possible. The
diagram below illustrates the entire menu structure of the UMX-2:
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UMX-2 Underwater Material & Coating Thickness Gauge
Top Level
STORE DIRECT CLEAR ZERO GAIN MATL UNITS MODE UMX-2
LOC NORTH LOC AUTO VLOW ALU IN P-E LT ON
SOUTH MANUAL LOW STL MM PECT LT OFF
EAST COATING MED STST E-E LTAUTO
WEST HIGH IRON MEMOFF
VHIGH CIRO E-E-E UPGRAD
PYC
PLST
PLUR
CUSTOM
Important comments:
• Depending on the transducer identified by the UMX-2, only the menu options
applicable to that specific transducer will appear. Therefore, it’s important to
note that the menus displayed are dynamic and may not be consistent if
different types of transducer are interchanged.
• Again, depending on the transducer identified, the modes applicable for that
specific probe type will be enabled and displayed. Dual element transducers
have mode options of P-E, PECT, or E-E. While the single element
membrane transducer options will only use our special TCG (time corrected
gain) triple echo mode (E-E-E), and all three modes listed above will be
deactivated and not displayed.
• If the MEMOFF has been activated, the data logging section of the gauge will
be temporarily turned off. This would be deactivated only if the user does not
intend to store measurements in the UMX-2. As a result, MEMOFF will
become the first ‘top level’ menu option, in place of a storage cell location (i.e.
A 1). Additionally, the top level menu items ‘DIRECT’ and ‘CLEAR’ will also
be temporarily deactivated from the menu options, as they pertain only to the
data storage facility of the UMX-2.
• If a custom material type has not been uploaded into the UMX-2, it will not
appear in the MATL subdirectory.
In general, if features and menu options start appearing/disappearing, as options
are activated/deactivated, it’s entirely based on the configuration settings and
probe identified by the UMX-2. The objective is to eliminate those items from the
menu structure that do not pertain to the mode or features activated/deactivated
by the user . It’s our effort to keep the available menu structure ‘simple’ and
‘intuitive’. All the features of UMX-2 will be further explain ed in later section of this
manual.
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STORE
DIRECT
CLEAR
ZERO
GAIN
MATL
UNITS
MODE
UMX-2
STORE
CLEAR
CHAPTER FOUR
MENU & CONNECTOR REFERENCE
4.1 Menu Options
Top Level
LOC
Store: This menu displ ays the current storage location of the UMX-2. This location
can refer to either a ‘grid’ cell location, like an Excel spreadsheet, or a sequential
format location, depending on which file format was uploaded into the gauge. If the
storage facility has been turned off, the menu label will read “MEMOFF”. The UMX-
2 will be shipped from the factory with a preloaded ‘grid’ file structure. Refer to the
section on page 43, for a detailed explanation.
DIRECT
NORTH
SOUTH
EAST
WEST
Direct: This menu item is also part of the data storage facility. It specifies which
direction to advance the cursor, after a measurement is stored. If a two dimensional
grid format is being used, all direction options can be used. However if a ‘sequential’
file format is used, only north and south are applicable. This menu item will not
appear if data storage has been disabled by the user. Refer to the section on page
52, for a det ailed explanation.
LOC
Clear: Again, this menu item is also part of the data storage facility. If a
measurement is stored by mistake, or in the wrong location, the measurement can be
cleared from memory using this option. The direction menu would be used to
advance to the location, and the ‘clear’ option would be used to erase the stored
measurement. If data storage has been disabled by the user, this menu item will not
appear as an option. Refer to the section on page 54, for a detailed explanation.
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UMX-2 Underwater Material & Coating Thickness Gauge
ZERO
AUTO
MANUAL
COATIN
Zero: The UMX-2 can use two different types of transducers, a dual or single
element. This menu item will only be visible if the UMX-2 identified a dual element
transducer connected.
• Auto – The auto zero feature of the UMX-2, performs an “off block” electronic
zero automatically, eliminating the need for a manual zero on a specified disk
or block. When the UMX-2 boots up, it will perform an auto zero during the
boot sequence. However, another auto zero may be need to account for
changes in temperature, or an incorrect zero due to couplant on the end of the
transducer during the zeroing process. Refer to the section on page 25, for a
detailed explanation.
• Manual – The UMX-2 is also equipped with an “on block” manual zero option.
This zero would only be used to reset the internal zero for of the UMX-2, as a
reference point for the auto zero. Note: the reference disk is located on the
end of the UMX-2 enclosure. Refer to the section on page 25, for a detailed
explanation.
• Coating - In order to account for very slight electronic differences in
transducers of the same type, frequency, and diameter, the UMX-2 has been
equipped with a “zero coating” feature. This zero is only used when the PECT
coating mode feature is being used. Although the coating thickness is not
displayed on the UMX-2 actual LCD displays, the coating thickness is stored
with the base material thickness when a measurement is saved to memory.
Once the data is downloaded to a PC, the coating thickness will be displayed
with PECT measurement stored. Refer to the section on page 40, for a
detailed explanation.
GAIN
VLOW
LOW
MED
HIGH
VHIGH
Gain: A 5 position gain switch in 2 db increments from 40 to 50 dB. Increase for
better penetration or punch, and decrease to eliminate unwanted noise or better
resolution. Refer to page 32 for further info.
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MATL
ALU
STL
STST
IRON
CIRO
PYC
PLST
PLUR
CUSTOM
Material: The UMX-2 includes a list of common material types with standard set
velocities. It’s important to note that the velocities associated with these materials
are general velocity values only. Materials of the same type, can have varying
grades and consistencies. As a result, the material velocity will also have slight
variations. A custom velocity has been implemented for this reason, and can be
programmed via DakView3 PC software. Refer to page 28 for further info.
UNITS
IN
MM
Units: Toggle between English or Metric units. The readout will change from inches
to millimeters. Refer to page 34 for further info.
MODE
P-E
PECT
E-E
E-E-E
Mode: The UMX-2 is equipped with a number of advanced measurement modes, to
satisfy a variety of application scenarios. The following is a brief description of each
mode. Refer to page 22 for further info:
• P-E (Pulse-Echo) – Common mode for measuring non-coated material (bare
metals).
• PECT (Pulse-Echo Coating) – A special mode used on coated materials to
measure the thickness of both; the base material and coating.
• E-E (Echo-Echo) – Common mode for measuring coated materials, and
measuring the base material only, without having to remove the coating.
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UMX-2 Underwater Material & Coating Thickness Gauge
• E-E-E (Triple Echo) – Special multiple echo mode used only with our single
element membrane transducers.
UMX-2
LT ON
LT OFF
LTAUTO
MEMOFF
UPGRAD
UMX-2: This is a general utility menu for miscellaneous features and functions.
The following is a brief explanation of each sub menu item. Refer to page 32 for
further information on upgrading the UMX-2:
• LT ON – Enables all the LED’s and display back lights.
• LT OFF – Disables all the LED’s and display back lights.
• LTAUTO – Powers all the LED’s and display back lights ‘on’ only when an
echo is detected (measurement). Refer to page 35 for further info.
• MEMOFF/ON - Toggles the data storage facility On or Off. Refer to page
51 for further info.
• UPGRAD – Feature to upgrade the firmware in the UMX-2 to the latest
version. Refer to page 65 for further info.
4.2 Top & Bottom End Caps
Top End Cap Bottom End Cap
The top & bottom inside end caps are where all connections are made to the UMX-2.
The bottom outside end cap also has a ‘zero reference standard’ attached. The
diagram above shows the layout and description of the connectors and zero
standard:
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Top End Cap :
Transducer Connectors
The transducer connectors and single control button are located on the top end cap
of the UMX-2. The transducer connectors are a special underwater Lemo “00”.
Note: There is no polarity associated with connecting a dual element transducer. If
a single element membrane style is connected, the dongle ‘must’ be plugged into the
connector labeled in the diagram above, in order for the UMX-2 to ‘auto identify’ the
single element probe type.
Single Control Button
The special magnetic reed found on the top end cap, provides single button
operation. Using this button and 3 basic press sequence options, the user can power
the UMX-2 on/off, enter the menu options, and change settings.
Bottom Outside End Cap:
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UMX-2 Underwater Material & Coating Thickness Gauge
Probe Zero Disk
The UMX-2 is equipped with an Auto Zero, which eliminates the user from having to
manually perform a zero on a specified zero standard. However, a Manual Zero
option has also been included with the UMX-2. This provides the user with the ability
to reset the internal zero used for the auto zero as a reset option. Other than for the
purposes of a safety mechanism, the Auto Zero feature will be used.
Bottom Inside End Cap:
Battery Cover
Simply remove the cover using a standard slot screw driver or other, and replace the
batteries.
Important: be sure the positive (+) battery terminal is facing up towards the battery
cover, when inserting them into the battery tube. This is very important! Failure to do
so will result in battery acid leakage cause by a current overload. The leakage can
permanently damage the circuit boards, should it leak through the battery tube. The
photo above shows demonstrates the polarity of the batteries. There is also a label
on the side of the battery tube for reference.
Note: Rechargeable batteries can be used, however they must be recharged outside
of the unit in a stand alone battery charger.
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Dakota Ultrasonics
RS-232 Connector
Refer to Diagram: The RS-232 connector is a 2 pin female LEMO connector. It is
designed to connect directly from the UMX-2 to a standard AT serial port on a PC or
into the supplied Serial to USB converter cable. There are two cables supplied with
the UMX-2;
• 2 pin LEMO to 9 pin serial cable
• 9 pin serial to USB converter cable.
Note: This connector is also used to upgrade the UMX-2 to the latest version of
firmware.
Serial to USB Converter Cable
A converter cable can be attached to the 9 pin serial cable, for computers that don
not have a serial port (part no. N-402-0510). This cable option is included in our kit
as standard.
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CHAPTER FIVE
PRINCIPALS OF ULTRASONIC MEASUREMENT
5.1 Time versus thickness relationship
Ultrasonic thickness measurements depend on measuring the length of time it takes
for sound to travel through the material being tested. The ratio of the thickness
versus the time is known as the sound velocity. In order to make accurate
measurements, a sound velocity must be determined and entered into the
instrument.
The accuracy of a thickness measurement therefore depends on having a consistent
sound velocity. Some materials are not as consistent as others and accuracy will be
marginal. For example, some cast materials are very granular and porous and as a
result have inconsistent sound velocities.
While there are many different ultrasonic techniques to measure thickness, which will
be discussed below, all of them rely on using the sound velocity to convert from time
to thickness.
5.2 Suitability of materials
Ultrasonic thickness measurements rely on passing a sound wave through the
material being measured. Not all materials are good at transmitting sound.
Ultrasonic thickness measurement is practical in a wide variety of materials including
metals, plastics, and glass. Materials that are difficult include some cast materials,
concrete, wood, fiberglass, and some rubber.
5.3 Range of measurement and accuracy
The overall measurement capabilities, based on the wide variety of materials, is
determined by the consistency of the material being measured
The range of thickness that can be measured ultrasonically depends on the material
as well as the technique being used and the type of transducer. Thickness
measurements can be made from a minimum of 0.010 in ch to 9.999” in steel.
However, the maximum attainable thickness is much less for more attenuative
materials (materials that absorb sound).
Accuracy, is determined by how consistent the sound velocity is through the sound
path being measured, and is a function of the overall thickness of the material. For
example, the velocity in steel is typically within 0.5% while the velocity in cast iron
can vary by 4%.
5.4 Couplant
All ultrasonic applications require some medium to couple the sound from the
transducer to the test piece. When the UMX-2 is used underwater as intended, the
water itself acts as a couplant. However when the UMX-2 is used above water, it
couplant will be required. Typically a high viscosity liquid is used as the medium.
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Dakota Ultrasonics
The sound frequencies used in ultrasonic thickness measurement do not travel
through air efficiently. By using a liquid couplant between the transducer and test
piece the amount of ultrasound entering the test piece is much greater.
5.5 Temperature
Temperature has an effect on sound velocity. The higher the temperature, the slower
sound travels in a material. High temperatures can also damage transducers and
present a problem for various liquid couplants.
Since the sound velocity varies with temperature it is important to calibrate at the
same temperature as the material being measured.
Normal temperature range
Most standard transducers will operate from 0°F to 180°F.
High temperature measurements
Special transducers and couplants are available for temperatures above 180°F up to
650°F with intermittent contact. It is necessary to cool the transducer, by submerging
the transducer in water between readings, when measuring high temperatures.
Modes and temperature errors
In addition to errors caused by velocity changing with temperature, some modes
(measurement techniques) are affected more than others. For example, dual
element pulse-echo mode has larger errors due to changes in the temperature of the
delay line. However, multi-echo techniques offer temperature compensation help to
minimize these errors.
5.6 Measurement Modes
In this section we will discuss the different measurements modes the UMX-2 is
capable of operating in, the transducers required, and the reasons for using specific
modes:
Pulse-Echo Mode (Flaw & Pit detection) – Coating Off (P-E)
Pulse-echo mode measures from the initial pulse (sometimes referred to as an
artificial zero) to the first echo (reflection). In this mode, either an automatic or
manual zero can be performed depending on the zero probe function setting. If the
manual mode has been selected, the transducer is placed on a reference disk,
located on bottom end cap of the UMX-2, and a manual zero is performed by
selecting the ‘manual’ sub menu option located in the ‘zero’ menu. If the Auto Zero
feature is enabled, a ‘zero reference standard’ is not necessary.
In this mode errors result from surface coatings and temperature variations.
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