FTS DTS-12 User manual

1.800.548.4264
www.ftshydrology.com
700-DTS-12 Rev. 20, 08 Jan 2014
DTS-12
SDI Turbidity Sensor
User Manual

Contact information
FTS
1065 Henry Eng Place
Victoria, B.C., V9B 6B2
CANADA
www.ftshydrology.com
Toll-free
1-800-548-4264
Local
250-478-5561
Technical support
support.ftshydrology.com

Revision History
Date
Person
Description
27 Jan 2012
RG
Update for DTS-12A and format to current standard
10 Dec 2012
PB
Correction made to BES equation on pg 12
16 May 2013
CV
Clarification improvements and added appendices
13 June 2013
CV
Updated cable connect/disconnect instructions and deployment guide
12 July 2013
CV
Updated deployment guide drawings
08 Jan 2013
CV
Corrected typo in DTS request data response

Table of contents
Contact information ........................................................................................................................................... ii
Chapter 1 Operation ................................................................................................................................... 5
1.1 General description ...........................................................................................................................................................6
1.2 Unpacking .............................................................................................................................................................................7
1.3 Installation.............................................................................................................................................................................7
1.4 SDI Connection....................................................................................................................................................................9
1.5 Operation............................................................................................................................................................................11
1.6 Address configuration ...................................................................................................................................................12
1.7 Calibration and maintenance .....................................................................................................................................12
1.8 Replacement Parts ..........................................................................................................................................................14
Chapter 2 SDI Commands ........................................................................................................................ 15
2.1 Notation for SDI commands........................................................................................................................................16
2.2 Commands recognized by the DTS-12 ...................................................................................................................16
2.3 General SDI commands.................................................................................................................................................18
2.4 SDI measurement and data commands .................................................................................................................18
2.5 Extended command set ................................................................................................................................................21
Chapter 3 Technical specifications ........................................................................................................ 22
Appendix A
Commands recognized by the DTS-12 (historical) ..........................................................................................................25

Chapter 1 Operation
Chapter contents
1.1 General description ...........................................................................................................................................................6
1.2 Unpacking.............................................................................................................................................................................7
1.3 Installation ............................................................................................................................................................................7
1.4 SDI Connection ...................................................................................................................................................................9
1.4.1 SDI-12 connectorized cable
1.4.1.1 Cable connection
1.4.1.2 Cable disconnection
1.5 Operation ........................................................................................................................................................................... 11
1.5.1 Startup Operation of Turbidity Sensor
1.5.2 Turbidity measurement
1.5.3 DTS-12 calculations
1.6 Address configuration................................................................................................................................................... 12
1.7 Calibration and maintenance..................................................................................................................................... 12
1.8 Replacement Parts .......................................................................................................................................................... 14

DTS-12 User Manual Chapter 1 Operation
page 6
1.1 General description
The FTS DTS-12 Turbidity Sensor (DTS-12) measures turbidity and suspended solids concentrations in liquids. The
method used is called optical back scatter and employs a detector at 90 degrees to the incident light beam. In
practice what this means is that light is emitted into a liquid medium and any amount of reflection detected from
suspended matter is a measure of the turbidity of the medium. To achieve this result the latest in micro power,
solid state, and infrared laser technology is used. The laser light output is modulated and synchronously detected
so that any effects from ambient light conditions are minimized. The measurement range of the DTS-12 is 0 to
1500 NTU, making it ideal for stream and river applications.
The DTS-12 has a built in wiper that is useful for reducing the effects of silt build up and biological fouling of the
sensor optics. The DTS-12 is factory programmed with turbidity calibration coefficients. The micro controller
applies these coefficients to the raw measurement data and computes mean, median, maximum, minimum,
variance, and BES (Best Easy Systematic estimator). All turbidity data is returned in NTUs (Nephelometric Turbidity
Units).
All control and measurement functions of the DTS-12 are initiated by sending it a SDI-12 command. SDI-12 stands
for Serial Data Interface at 1200 baud. It is a standardized protocol that defines how microprocessor based sensors
can communicate with data loggers.
Figure 1-1: DTS-12 Turbidity Sensor

DTS-12 User Manual Chapter 1 Operation
page 7
1.2 Unpacking
You should have received the following materials with each DTS-12 sensor:
1. DTS-12 Turbidity 
2. Spare wiper blade.
3. DTS-12 SDI Turbidity Sensor Operating Manual.
1.3 Installation
In most cases the best deployment for a turbidity sensor is inside protective tubing (typically PVC pipe) that is
placed in the river and fastened securely to the shore by various means (concrete pillars, metal stakes etc.).
Figure 1-2 shows such an installation. If in doubt consult FTS regarding the best deployment options for your site.
The DTS-12 must be oriented such that the optical window has at least 4 inches axial end clearance and 2 inches
radial side clearance from any physical objects (e.g. the river bottom). The sensor should be located in an area that
is representative of the water to be measured.
Figure 1-2: Typical DTS-12 installation

DTS-12 User Manual Chapter 1 Operation
page 8
To aid in installation, FTS can supply a DTS-12 sensor deployment guidedeployment guide
conjunction with the user supplied and constructed 4-inch ID deployment tube. The deployment guide can be slid
down the inside of the protective tubing (typically schedule 40 Aluminum or PVC pipe) that is placed in the river.
Examples are shown in the figures below.
Figure 1-3: DTS-12 deployment guide (diagram)
Figure 1-4: ABS Deployment Guide installed on a DTS-12

DTS-12 User Manual Chapter 1 Operation
page 9
Figure 1-5: Typical DTS-12 deployment tube and deployment guide combination
1.4 SDI Connection
The SDI cable (nominally 25 feet long) may be connected to the DTS-12 by waterproof gland or underwater
connector. Normally the free end of the cable is shipped with a length of the polyurethane jacket removed to
expose the three 20 AWG conductors. This allows maximum flexibility when connecting to a data logger that uses
a terminal strip.
The SDI cable may be optionally terminated with a 3-pin military connector for connection to similar connector on
the data logger. Cable wire colour coding and FTS standard connector
1
pinouts are shown in the table and
diagram below:
Wire colour
Pin1
Function
Red
A
+12 V DC power supply
White
B
Data
Black
C
Ground
1
Waterproof military-style bayonet connector 851-06JC8-3AP50; FTS part number 520-83AP; compatible with FTS
Axiom dataloggers.

DTS-12 User Manual Chapter 1 Operation
page 10
1.4.1 SDI-12 connectorized cable
The DTS-12 can be ordered with fixed length connectorized cables (60 and 100 ft.) that allow for quick disconnect
and re-connection. This watertight connection is submersible and permits easy sensor removal from a field
installation without removing the cable. In complex installations or on installations with long cable runs this is a
very desirable attribute.
A thin film of dielectric grease is placed on the End Cap Flange during connection at the factory. This facilitates
the operation of the connection and should be reapplied as needed to ensure the connection can be unplugged.
If doing so, ensure that the grease is kept out of contact with the electrical prongs and receptacles to avoid a poor
electrical connection.
Warning: Because of the tight fit of this connection, inexperienced users tend to twist and bend the connection
when connecting or disconnecting the cable. This inappropriate handling WILL damage the female
receptacles inside the Cable Connection.
See “How to connect and disconnect the DTS-12 turbidity sensor waterproof connectorized cable” video on the FTS
web page for proper procedure. http://www.ftsenvironmental.com/video/
1.4.1.1 Cable connection
Figure 1-6: Cable connection details