Geotech GTW User manual

Rev 3/12/2018 Part # 22100045
Portable Turbidity
Meter
Installation and Operation Manual

1

1
Table of Contents
DOCUMENTATION CONVENTIONS ................................................................... 2
Section 1: System Description........................................................................... 4
Function and Theory ......................................................................................... 4
Instrument Features .......................................................................................... 4
System Components......................................................................................... 4
Section 2: System Installation & Navigation ................................................... 4
Install the battery............................................................................................... 5
Sample Vial Handling........................................................................................ 5
User Interface.................................................................................................... 6
Section 3: System Operation.............................................................................. 7
3.1 Quick Start Guide........................................................................................ 7
3.2 Menu Navigation ......................................................................................... 8
3.3 USB Connection........................................................................................18
3.4 Menu Structure.......................................................................................... 19
Section 4: System Maintenance....................................................................... 20
Section 5: System Troubleshooting ................................................................ 21
Section 6: System Specifications .................................................................... 22
Section 7: Parts and Accessories.................................................................... 23
The Warranty...................................................................................................... 29

2
NOTE
DOCUMENTATION CONVENTIONS
This uses the following conventions to present information:
General Information
In no event will the manufacturer be liable for direct, indirect, special, incidental or
consequential damages resulting from any defect or omission in this manual. The
manufacturer reserves the right to make changes in this manual and the products it
describes at any time, without notice or obligation. Revised editions are found on the
manufacturer’s website.
An exclamation point icon indicates a WARNING of a situation
or condition that could lead to personal injury or death. You
should not proceed until you read and thoroughly understand the
WARNING message.
WARNING
CAUTION
A raised hand icon indicates CAUTION information that relates to
a situation or condition that could lead to equipment malfunction
or damage. You should not proceed until you read and thoroughly
understand the CAUTION message.
A note icon indicates NOTE information. Notes provide additional
or supplementary information about an activity or concept.

3
In order to ensure your Turbidity Meter has a long service life and operates
properly, adhere to the following cautions and read this manual before use.
Disconnect from power source when not in use.
Power input source must not exceed maximum ratings.
Equipment must be wired to a negative ground system.
Equipment may not operate properly with excess wiring not supplied by
manufacturer.
Avoid spraying fluid directly at equipment.
Never submerge equipment.
Avoid pulling on wires to unplug equipment wiring.
Avoid using equipment with obvious physical damage.
To prevent equipment damage, avoid dropping it.
WARNING
The following applies only to users in European countries:
This product is designated for separate collection at an appropriate collection
point. Do not dispose of as household waste.
For more information, contact the seller or the local authorities in charge of waste
management.
Do not operate this equipment if it has visible signs of significant
physical damage other than normal wear and tear.
Notice for consumers in Europe:
This symbol indicates that this product is to be collected
separately.

4
Section 1: System Description
Function and Theory
Geotech's Portable Turbidity Meter offers great precision, repeatability and ease of use in
a low cost extremely robust portable/laboratory instrument. Data points from field sample
events can be stored to memory and transferred to computer or other storage device.
Turbidity Meters provide fluid clarity insight by shining light onto a sample and measuring
the amount of light scattered by suspended particles in the fluid.
The Geotech Portable Turbidity Meter has two light source models to fulfill specific
customer and site requirements:
Model GTW: White Light source, compliant to US EPA method 180.1
Model GTI: Infrared light source, compliant to ISO 7027 standards
Instrument Features
Sample chamber with lid
Data port/ power supply (serial
output, USB to Mini-B cable not
included)
Sealed battery compartment (4x AA
batteries)
IP67 Seal for extension into
hazardous environments
Digital display and navigation keypad
System Components
Economy carry case included,
optional custom foam cut case
available
Lint-free cleaning cloth
2 sample vials
Primary Calibration Standards: 0.10,
20, 100, 800 NTU
Figure 1-1: Instrument Features

5
Section 2: System Installation & Navigation
Install the battery
1. With a small Phillips screwdriver, remove the battery cover (located on the backside
of the instrument).
Take care to keep the small screws and washers safe when removing the
battery cover.
2. Install four (4) AA alkaline or nickel metal hydride (NiMH) batteries.
Make sure that batteries are installed in the correct orientation.
3. Replace the battery cover.
For optimal seal, we recommend using a torque screwdriver set to 4N-m.
Sample Vial Handling
When placing the vials into the instrument, ensure that
the white line on the sample vial is aligned with the black
arrow on the bottom edge of the instrument’s sample
chamber.
The sample vials must be very clean while calibrating or
doing field readings; no debris or fingerprints should be
visible on the glass. Use a soft cleaning cloth to ensure
clarity before each measurement. Do no store samples
and vial in extreme temperatures or direct sunlight.
Figure 2-1: Replacing the batteries
Handle calibration and sample vials by caps only. Any scratches on the
vials will compromise accurate turbidity readings.

6
User Interface
1. DISPLAY
Displays readings, diagnostics, and operational data.
2. UP ARROW (▲)
Scroll through menus, enter numbers and letters
3. DOWN ARROW (▼)
Scroll through menus, enter numbers and letters
4. MENU
Enters into main menu function, selects options to configure the instrument, select
analysis, and moves cursor to the right.
5. SAVE
Store Selections and data, saves the result to be USB transferred and selects the
parameters.
6. ESC/OFF
Powers off the instrument (hold for 3 seconds), aborts operations, return to the
previous screen.
7. READ/ON
Powers on the instrument (hold for 3 seconds), confirms options, initiates sample
reading, moves cursor to the left.
Figure 2-3: Instrument Keypad
Figure 2-2: Sample chamber
alignment

7
Section 3: System Operation
3.1 Quick Start Guide
To turn ON unit: press and hold the READ button for 3 seconds.
To turn OFF unit: press and hold the ESC button for 3 seconds.
Basic Operation
1. Turn instrument on by pressing READ for 3 seconds.
a. Once through the welcome screens, the unit will automatically
begin reading a sample.
b. See Section 3.2.2: Calibrate if Calibration is required.
2. Rinse the inside of each sample vial three times with the sample to be
tested.
3. Completely fill sample vial with sample, then dry and clean the outside of
vial.
Handle vial by the cap.
4. Align white mark on vial with arrow on bottom of sample chamber.
See “Sample Vial Handling” in Section 2: System Installation &
Navigation for details.
5. Close the sample chamber cap.
6. Press READ button again to take sample, NTU reading will appear after
status bar is complete.
7. Press SAVE button to mark reading, “M” will flash for 3 seconds in upper
left corner of display.
Figure 3-1: Basic Operation
Figure 3-1: Read (ON/Enter) ESC (OFF/Back)

8
3.2 Menu Navigation
The Geotech Portable Turbidity Meter has several configuration capabilities. The menu
structure is easy and simple to operate, please follow the steps below to configure the unit
according to your needs.
To Enter Main Menu: With instrument turned on, press MENU key for 3 seconds to enter
the Menu Function. You will see the following screen:
Using ▲ or ▼ the user can navigate between the main menu functions. When you reach
the desired menu or function press READ to enter, or ESC to go back to the previous
screen.
The four main sub menus are listed below:
ID - Access the user identification function
Calibrate - Access the calibration functions
Config - Access the configuration functions
Service - Access the service functions (only for certified technicians)
The fifth menu item is “Back” – when selected will navigate to the ready-to-sample screen.
Please reference the following pages for an explanation of instrument configuration and
menu navigation. See section 3.4: Menu Structure for an overview of the complete menu
structure.
3.2.1 ID (Identification)
From the main menu, use the ▲ or ▼ keys select the ID function, then press READ to
enter that submenu.
Sample
Use the ▲ or ▼ keys to set sample number from 0-99. Use the READ or
SAVE button to set the sample number and exit to the ID menu.
Main Menu
ID
Calibrate
Config
Service