Turner Designs Little Dipper 2 User manual

Little Dipper2 In-Line Fluorometer
December 7, 2018
P/N 998-2821
Version D
TURNER DESIGNS
1995 N. 1st Street
San Jose, CA 95112
Phone: [phone]
FAX: [phone]

Table of Contents
1.
Introduction
1.1
Introduction
4
1.2
Inspection and Setup
4
2.
Installation and Operation
2.1
Installation
5
2.2
Tee Installation
5
2.3
Operation
6
3.
Little Dipper 2 Calibration Software and Calculations
3.1
Software Requirements and PC Installation
7
3.1.1
Minimum PC Requirements
7
3.1.2
Software and Calibration Cable Installation
7
3.1.3
PC Software Interface
7
3.2
Calibration
9
3.3
Calculating Concentration Coefficients
12
4.
Recommended Measurement Practices
4.1
Minimizing Variation in Signal
13
4.2
Temperature Considerations
13
5.
Maintenance and Warranty
5.1
Maintenance Check Using Standard Solutions
15
5.2
Visual Inspection and Cleaning
15
5.3
Warranty Terms
16
5.4
Warranty Service
16
5.5
Out of Warranty Service
17
Appendices
A
Fluorometer and Mounting Tee Specifications
19
B
Wiring Guide
20
C
How to Determine Your Version of Window OS
21
D
Tee modification
23
E
General Information for Calibrating with LD2 Control Box
24

998-2821 Rev. D Page 3
WASTE ELECTRICAL AND ELECTRONIC EQUIPMENT (WEEE) DIRECTIVE
Turner Designs is in the business of designing and selling products that benefit the well-
being of our environment. Accordingly, we are concerned with preserving the
surroundings wherever our instruments are used and happy to work with customers by
complying with the WEEE Directive to reduce the environmental impact resulting from
the use of our products.
WEEE Return Process:
To arrange the return of an end-of-life product, proceed as follows:
If you purchased your instrument through a Turner Designs Distributor please
contact your local representative. They will instruct you where to return the end-of-
life product.
If you purchased your instrument directly from Turner Designs please contact Turner
Designs Customer Service:
By Phone: [phone] or Toll Free: [phone]
By Email: Customer Service at [email protected]
Turner Designs will provide a WEEE RMA Number, a Shipping Account Number,
and a Ship to Address. Package and ship the product back to Turner Designs.
The product will be dealt with per Turner Designs’ end-of-life recycling program in an
environmentally friendly way.

998-2821 Rev. D Page 4
1. Introduction
1.1 Description
Turner Designs’ Little Dipper2 is an accurate, single-channel fluorometer designed
to measure the concentration of your fluorophore of interest. The Little Dipper2
provides a 4 - 20 mA output signal proportional to the concentration of the
fluorophore in the sample or source water. In a representative application, Little
Dipper2 can be used with a data collection system to monitor and control the level
of treatment chemicals in industrial applications. The sample water’s fluorescence
intensity is measured by passing the sample water, containing the fluorophore of
interest, past the Little Dipper’s optical window. An excitation light source illuminates
the solution and excites the fluorophore in the solution which fluoresces at a different
wavelength. The intensity of the emitted light is proportional to the concentration of
the fluorophore in the sample or source water. Turner Designs’ Little Dipper2 has
a low maintenance design that will provide trouble-free performance.
1.2 Inspection and Setup
Part Number
Dynamic Range
Factory Adjusted
2820-000-A
< 1 to 300 ppb typical for PTSA
< 1-200ppb (18.0mA –19.5mA)
2820-000-F
< 1 to 100ppb typical for Fluorescein
< 1-100ppb (18.0mA –19.5mA)
If your application requires a different concentration range, the Calibration
Cable kit P/N 2820-505 is required. Contact Accessory Sales to purchase.
Refer to calibration procedure in Section 3. Refer to Appendix E if integrating
with a Control Box.
Little Dipper2 Fluorometer
with label specifying serial
number of unit
4-20mA cable P/N 021-2800
5-foot long cable with 4 bare
leads: Black, Red, Orange
and Brown
1 in. (NPT) mounting tee for
flow through measurements.
Threaded Connection Ring
Calibration Cable Kit P/N 2820-505
12v Power Supply
Calibration Cable

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2. Installation and Operation
2.1 Installation
Turner Designs’ Little Dipper2 is rated for light industrial environments.
Do not install the Little Dipper2:
In direct sunlight or near heat sources - operating temperature 0-50 °C.
On vibrating walls or surfaces that affect the flow.
Near devices that produce a strong electromagnetic field, such as large
generators.
It is recommended that the Little Dipper2 be installed in such a way that the flow is
directed upward to expel any trapped air bubbles or air trapped on the optical
window will influence signal and cause erratic readings - see Section 4.0.
2.2 Tee Installation
We recommend the following installation procedure for installing the Little Dipper2
onto the mounting tee provided for flow through applications:
1)
2) Connect the mounting tee in line with your flow and start flowing water.
3) Inspect for leaks.
Note: In the event the Little Dipper2 must be removed for service,
the mounting tee opening can be plugged with Plumbing Plug P/N 2820-
520. Contact Accessory Sales to purchase.
Make sure that the o-ring
is installed in the tee.
Insert the Little Dipper 2
into the tee. Make sure to
align the slot on the tee with
the tab on the Little Dipper 2.
Lower the ring over the
top of the Little Dipper 2
and hand tighten.
DO NOT USE TOOL TO TIGHTEN.
Plumbing Plug P/N 2820-520

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4) Connect the 4-20mA cable to the top of the Little Dipper2.
5) Connect the Little Dipper2 to the power supply and digital multimeter as shown
below.
Note: The power ground (Black Wire) and the 4-20 mA return (Brown Wire) are
not common. These wires should not be connected to the same point. Do not
allow the bare wires to touch each other or conductive surfaces. Use standard
electrical connection and insulation materials. Failure to properly connect the
Little Dipper 2 may result in damaged equipment.
2.3 Operation
Turner Designs’ Little Dipper2 uses a Light Emitting Diode (LED) at a specific
wavelength to excite the fluorophore of interest in samples or source water. Upon
excitation, the fluorophore emits a different wavelength of light (fluorescence) that
will be detected by the fluorometer’s photodiode.
After power (8 - 30 VDC) is applied to the Little Dipper2 allow 5 seconds for the
LED to stabilize. After 5 seconds measurements can be taken continuously as
current output (4 –20 mA).
Multimeter
Common
20 mA
A
DC Power Supply
+_
12 VDC 0.2 A
BLACK
BROWN
RED
ORANGE
Direction of
flow
When connecting the Little Dipper 2 to the cable,
pay special attention to the orientation of the pins.
Once the connection is made, slide the
collar down and rotate the collar to secure.

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3. Calibration Software and Calculations
The Little Dipper2 is factory adjusted to the following concentrations:
2820-000-A 200ppb PTSA(18.0mA –19.5mA)
2820-000-F 100ppb Fluorescein (18.0mA –19.5mA)
If your application requires a different concentration range, the Calibration Cable kit P/N
2820-505 is required. Contact Accessory Sales to purchase. Refer to calibration
instructions below:
Note: Refer to Appendix E if integrating with
a Control Box.
3.1 Software Requirements and PC Installation
The LD2 software user interface has been designed to work with Windows-based systems.
At this time there is no Macintosh version available.
3.1.1 Minimum PC Requirements
Intel®Pentium®133 MHz microprocessor
Microsoft®Windows®98 or higher
32 MB of RAM
800 x 600 SVGA resolution
3.1.2 Software and Calibration Cable Installation
Included on the USB flash drive are:
LD2 application
Driver installer for 32-bit Windows OS
Driver installer for 64-bit Windows OS
Release Notes
License Agreement
1. Exit all Windowsprograms
2. Plug the USB connector of Calibration Cable into your computer.
3. Insert the USB Flash Drive (also located on the Turner Designs Customer Care
Software / Firmware webpage under Little Dipper2).
4. If you’re running 64-bit Windows OS, double-click the
CP210xVCPInstaller_x64.exe icon to install the correct driver for your operating
system. If you’re running 32-bit Windows OS, double-click the
CP210xVCPInstaller_x86.exe icon.
Calibration Cable Kit P/N 2820-505
12v Power Supply
Calibration Cable

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Note: If you are not sure which OS your computer is running, please follow
the instructions in Appendix C.
5. A screen will appear prompting you to begin the installation process. Click
“Next.”
6. Follow the screen prompts to install the driver software. The software will be
automatically installed on your computer’s C drive.
7. You will see a “Completing the Installation of the CP210x USB to UART Bridge
Driver” screen upon successful completion of installation. Click “Finish.”
8. Return to the USB flash drive window and open the LD2 software folder and
double click on the “Setup.exe”icon.
9. Follow the screen prompts to install the LD2 application and the accompanying
National Instruments application. The software will be automatically installed on
your computer’s C drive. If you wish to specify an alternate location for the
installation, click the “Browse” button and type in the desired location.
10. Once the installation process is complete, restart the computer and locate the
LD2 application icon on your desktop or in your applications folder.
3.1.3 PC Software Interface
1. Plug the Calibration Cable into your computer.
2. Plug the Calibration Cable onto the connector of the Little Dipper2.

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3. Begin LD2 software by double-clicking on the LD2 icon.
4. Plug the 12V power supply into a power source and supply power to the
calibration cable.
5. Wait for initialization process to complete.
6. Select the Connect to Device button. The Device Connection Status will turn
green when connection is established and “Device is now connected” will appear
in the dialog box.
3.2 Calibration
Once the connection to the Little Dipper2 has been established in the LD2 Software you
can proceed with calibration.
1) Obtain a glass beaker with a known volume of the
source water you will be measuring.
Place the beaker on a non-reflective black surface.
Note: This water should represent the signal
you intend to set as zero, make sure that it
does not contain any fluorophore.
2) Fully submerge the optical face in the water.
IMPORTANT NOTE: MAKE SURE TO REMOVE ALL BUBBLES FROM THE OPTICAL
FACE BY TILTING THE LITTLE DIPPERTM 2 AND GENTLY SHAKING WHILE FULLY
SUBMERGED IN THE WATER AS AIR BUBBLES TRAPPED NEAR OR ON THE
OPTICAL HEAD WILL INFLUENCE RESULTS.

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3) Once bubbles have been removed select the Blank Calibration button from the LD2
software screen. The dialog box will then state “Blank Calibration…Please wait”.
4) Once the blank calibration is complete the following screen will appear:
5) Remove the Little Dipper2 from the beaker.
6) In the same beaker which contains a known volume of your source water, make a
solution using your fluorophore of interest that represents a concentration you intend to
measure or use Turner Designs prepared calibration standards. Contact Accessory
Sales to purchase.
7) Place the beaker on a non-reflective black
surface. Ensure the solution is well mixed,
submerge the Little Dipper2 into the solution.
IMPORTANT NOTE: MAKE SURE TO REMOVE ALL BUBBLES FROM THE OPTICAL
FACE BY TILTING THE LITTLE DIPPERTM 2 AND GENTLY SHAKING WHILE FULLY
SUBMERGED IN THE WATER AS AIR BUBBLES TRAPPED NEAR OR ON THE
OPTICAL HEAD WILL INFLUENCE RESULTS.

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8) Once bubbles have been removed, enter the value for mA at which your calibration
solution should be set. Select the Solution Calibration button from the LD2 software
screen. The dialog box will then state “Solution Calibration…Please wait”.
9) Once the solution calibration is complete the following screen will appear:
10)You can now install the Little Dipper2 in line with the system you intend to monitor
following installation instructions provided - see Section 2.2.
Data collected upon completing these calibration steps can be put into a table similar to the
table below.
Table 1: Example of data collected from calibration Steps 1-10.
Solution Measured
Concentration
Multimeter current output
Blank Solution
Cb(0 ppb)
Rb(4 mA)
Sample Solution
Cs(100 ppb)
Rs(19 mA)

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3.3 Calculating Concentration Coefficients
You can find the coefficients required for calculating concentrations using the equation:
Equation 1: y = mx + c
Where:
y = the sample concentration,
m = the slope of your equation,
x = the sensor output in mA,
c = the x intercept (offset) when y = 0.
Finding the slope of your equation using example data from Table 1:
Equation 2: m = [(Cs-Cb) / (Rs–Rb)]
m = [(100 - 0) / (19 - 4)] = 100/15 = 6.67
Finding the c constant using example data from Table 1:
Equation 3: 0 = [(m * Rb) –C]
0 = [(m * 4) –C]
c = 26.68
Substitute m and c from Equation 1 with end values from Equations 2 and 3:
Equation 4: y = 6.67x –26.8
You can now calculate y (ppb) concentrations simply by substituting sensor output (mA)
values for x in Equation 4.
For general information on how to calibrate your sensor using a control box, refer to
Appendix E.

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4. Recommended Measurement Practices
4.1 Minimizing Variations in Signal
Turner Designs’ Little Dipper2 has a flat surfaced optical window that might trap air
bubbles when positioned vertically. For this reason we recommend:
1) Installing Little Dipper2 horizontally so that the mounting tee is in a vertical position.
2) That the flow direction is upward through the mounting tee.
This will ensure than any trapped air bubbles will be released and will not interfere with
sample measurement.
4.2 Temperature Considerations
Fluorescence is temperature dependent. The fluorescence signal from most fluorophores
will decrease as sample temperature increases. However, fluorescence values can be
corrected for temperature effects if the temperature correction coefficient of the fluorophore
being measured is known. Table 2 lists known temperature correction coefficients. These
coefficients can be used with recorded temperatures in the following equation to correct
temperature effects on fluorescence values:
Fr = Fs * e [n (Ts-Tr)]
Where:
Fr = the calculated fluorescence at the reference temperature, Tr
Tr = the reference temperature
Ts = the sample temperature at time of reading Fs
Fs = the sample’s fluorescence at the time the temperature of the sample is measured, Ts.
e = the base of natural log
n = Temperature Coefficient for whatever dye is used - see Table 2.
For greatest accuracy, determine the Temperature Coefficient of the dye or fluorophore
being used, record the sample temperature, and correct the sensor output for changes in
Direction of water flow

998-2821 Rev. D Page 14
temperature. Additional information on how to apply these corrections is included in the
Turner Designs Application Note: A Practical Guide to Flow Measurements.
Table 2: Temperature Coefficients for specific dyes. Changes in the dye concentration are
exponential as opposed to linear.
Dye
Temperature Coefficient (n)
PTSA
-0.00126 / °C Exponential
Fluorescein
0.0036 / °C Exponential

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5. Maintenance and Warranty
The Little Dipper2 Fluorometer is designed for light industrial monitoring applications that
require continuous measurements. It provides maximum performance and solid state reliability
with minimal maintenance.
A maintenance check should be made once per month to ensure the optical window is free from
any chemical or biological fouling. Frequency of maintenance checks are dependent on the
fouling rate of the system being monitored. Systems that have a higher fouling rate might
require more frequent maintenance checks.
5.1 Maintenance Check Using Standard Solutions
You may check if the unit is responding correctly simply by running standard solutions past
the optical window.
1) Make a standard solution (solution of known concentration of the fluorophore being
measured) that is less than the maximum concentration set for the Little Dipper2.
2) Flow this solution past the optical window and record the mA reading
3) Calculate the solution concentration using your equation determined from Section 3.3
and compare to the actual solution concentration.
4) If the calculated concentration varies by more than 5% of the actual solution’s
concentration, see Section 5.2 for visual inspection and cleaning.
Maintenance checks are important and will ensure the Little Dipper  2 is continuing
to provide maximum performance and measurement reliability.
5.2 Visual Inspection and Cleaning
To visually check if the optical window has been fouled:
1) Remove the Little Dipper2 from the mounting tee.
2) If there is any noticeable fouling, use a soft bristle brush or non-abrasive cloth material
and soapy water to clean the optical window. Be sure to rinse thoroughly.
3) If the fouled window is unable to be cleaned with soapy water and the soft bristle brush,
make a 10% HCL solution and use that solution, in place of the soapy water, with the
soft bristle brush to clean the window.
Note: Hydrochloric acid is a hazardous material and should only be handled by
qualified personnel.
4) Once the optical window has been cleaned, re-install the mounting tee back onto the
Little Dipper2.
Note: See Section 2.2 on how to properly install the mounting tee.

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Note: In the event the Little Dipper  2 must be removed for service, the mounting
tee opening can be plugged with Plumbing Plug P/N 2820-520. Contact Accessory
Sales to purchase.
5.3 Warranty Terms
Turner Designs warrants the Little Dipper2 and accessories to be free from defects in
materials and workmanship under normal use and service for a period of 12 months from
the date of shipment from Turner Designs with the following restrictions:
Turner Designs is not responsible for replacing parts damaged by accident or
neglect. Your instrument must be installed according to instructions in the User’s
Manual. Damage from corrosion is not covered. Damage caused by customer
modification of the instrument is not covered.
This warranty covers only Turner Designs products and is not extended to equipment
used with our products. We are not responsible for incidental or consequential
damages, except in those states where this limitation is not allowed. This warranty
gives you specific legal rights and you may have other rights which vary from state to
state.
Damage incurred in shipping is not covered.
5.4 Warranty Service
To obtain service during the warranty period, the owner shall take the following steps:
1. Write, email or call the Turner Designs Technical Support department and describe as
precisely as possible the nature of the problem.
Phone: [phone]
Email: [e-mail]
2. Carry out any adjustments or tests as suggested by the Technical Support Department.
3. If proper performance is not obtained you will be issued a Return Materials Authorization
number (RMA) to reference. Package the unit, write the RMA number on the outside of
the shipping carton, and ship the instrument, prepaid, to Turner Designs. If the failure is
covered under the warranty terms, the instrument will be repaired and returned free of
charge, for all customers in the contiguous continental United States. For customers
outside of the contiguous continental United States customer pays for shipping duties
and documentation to Turner Designs. Turner Designs pays for return shipment
(custom duties, taxes and fees are the responsibility of the customer).
Plumbing Plug P/N 2820-520

998-2821 Rev. D Page 17
5.5 Out of Warranty Service
Follow steps for Warranty Service as listed above. If our Technical Support department can
assist you by phone or correspondence, we will be glad to, at no charge. Repair service will
be billed on a fixed price basis, plus any applicable duties and/or taxes. Shipment to Turner
Designs should be prepaid. Your bill will include return shipment freight charges.
Address for Shipment:
Turner Designs, Inc.
1995 N. 1st Street
San Jose, CA 95112

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Equipment Specified as Electrical and Electronic Waste

998-2821 Rev. D Page 19
Appendix A: Fluorometer and Mounting Tee Specifications
Parameter
Specification
Linearity (over dynamic range)
0.99 r2
Power Draw
0.88 W @ 12 VDC (1.0 W max.)
Input Voltage
8 –30 VDC
Signal Output
4 –20 mA
Light Source
Light Emitting Diode
Detector
Photodiode
Warm up time
5 seconds
Dimensions
Length: 8.63 in. (21.9 cm)
Diameter (housing): 1.30 in. (3.3 cm)
Diameter (flange): 1.72 in. (4.4 cm)
Weight
4.4 oz. (125 g)
Material
PVC –Type I, Rigid injection-molded plastic
Mounting Tee Specifications
Parameter
Specification
Material
PVC –Type I, Rigid injection-molded plastic
Threading
1 inch (NPT)
Length
3.30 in. (8.4 cm)
Dynamic Pressure Rating
100 PSI

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Appendix B: Wiring Guide
Wire Color
Function
Connection
Red
Supply Voltage
8 –30 VDC
PSU –Positive Connection
Black
Supply Ground
0 VDC
PSU –Ground Connection
Orange
Signal out to data logger,
“A”, 4 – 20 mA DC
Multimeter “A” Connection
Green/Brown
Signal out to data logger,
“Common”, 4 – 20 mA DC
Multimeter “Common”
Connection