OTT CTD User manual

Operating instructions
Groundwater datalogger
OTT CTD
English

These operating instructions (version "01-1009") cover the OTT CTD software
versions
OTT CTD firmware from V 1.00.0
OTT CTD operating program from V 1.50.0
The OTT CTD firmware version can be found in the "Advanced operation" mode,
"OTT CTD" window of the operating program. The version of the operating
program can be found via the "Info" function in the "Help" menu.
We reserve the right to make technical changes and improvements without notice.

Table of contents
1 Scope of supply 4
2 Order numbers 4
3 Safety information 5
4 Introduction 6
5 Installing, checking, and exchanging batteries 8
6 Installing the OTT CTD 10
6.1 Installing in 1" observation wells 12
6.2 Installing in 2", 3", 4", 5" or 6" observation wells,
top cap with adapter plate recess 13
6.3 Installing in observation wells beginning at 2" diameter,
top cap without adapter plate recess 15
6.4 Installing in observation wells beginning at 2" diameter without a top cap 17
7 Setting OTT CTD operating parameters 18
7.1 Installing the OTT CTD operating program 18
7.2 Establishing a communication link from PC to OTT CTD 18
7.3 Setting OTT CTD operating parameters 20
7.4 Saving/loading OTT CTD configuration 24
7.5 Importing/exporting OTT CTD configuration 24
8 Determining and displaying instantaneous values (observer function) 26
9 Reading out data 28
10 Exporting data 29
11 Displaying data 30
12 Protecting the OTT CTD and OTT CTD operating program with a password 31
13 Date and time settings 33
14 Deleting the data memory 34
15 Installing new OTT CTD firmware 34
16 Maintenance work 35
16.1 Cleaning the pressure probe 35
16.2 Replacing the desiccant capsules 36
16.3 Checking/replacing the batteries 36
16.4 Calibrating the conductivity sensor 36
17 Error messages 38
18 Troubleshooting/fault correction 38
19 Repair 40
20 Notes about the disposal of old units 40
21 Technical data 41
Appendix A – Declaration of conformity for OTT CTD 43
3

4
1 Scope of supply
OTT CTD – 1 groundwater datalogger consisting of a communication unit with installed
O-ring, pressure probe cable with pressure compensation capillary and
Kevlar core for longitudinal stabilization, 2 desiccant capsules, pressure probe
with integrated conductivity sensor and datalogger
– 3 x 1.5 V batteries, alkaline (LR6 · AA) or lithium design (FR6 · AA)
– 1 brief Instructions
– 1 factory acceptance test certificate (FAT)
2 Order numbers
OTT CTD Groundwater datalogger 55.445.001.9.0
Information needed for order
– Measuring range:0 … 4 m;
0 … 10 m;
0 … 20 m;
0 … 40 m;
0 … 100 m
– System length: 1,5 … 200 m (±1 % ±5 cm)
– Battery type: alkaline, lithium
Accessories Installation kit 55.440.025.9.2
consisting of: adapter ring 1", adapter
plates 2", 4", 6", suspension bracket
Adapter plates 3" and 5" 55.440.444.4.1
Suspension brackets 55.440.450.4.1
for top caps starting at 2" without recess
and for universal installation
Cable suspension unit on request
for OTT CTD system lengths of > 100 m
CD-ROM „OTT CTD Software“ 56.571.000.9.7
OTT CTD operating program for PC
Top cap
with integrated fastening hook
– for 2" observation wells 24.220.052.9.5
– for 4" observation wells 24.220.054.9.5
– for 6" observation wells 24.220.057.9.5
Intelligent top cap OTT ITC 55.530.0xx.3.2
for GSM remote data transfer
5-sided key 20.250.095.4.1
to lock OTT top caps
Optical OTT Duolink reading head 55.520.017.4.2
Optical OTT IrDA link USB reading head 55.520.026.9.2
Calibration container 55.445.025.9.2

5
Alkaline battery 96.800.004.9.5
LR6 · AA; 3 units required
Lithium battery 97.800.008.9.5
FR6 · AA; 3 units required
Desiccant capsules 97.100.280.9.5
2 in aluminum bags
Conductivity calibration solution
– 0,1 mS/cm; 1000 ml 55.495.350.9.5
– 0,5 mS/cm; 946 ml 55.495.351.9.5
– 1,412 mS/cm; 1000 ml 55.495.352.9.5
–12,856 mS/cm; 946 ml 55.495.353.9.5
– 47,6 mS/cm; 1000 ml 55.495.354.9.5
3 Basic safety information
Read these operating instructions before using the OTT CTD for the first time!
Become completely familiar with the installation and operation of the OTT CTD
and its accessories! Retain these operating instructions for later reference.
The OTT CTD is used to measure groundwater levels, the water temperature
and the specific conductivity of the groundwater. Only use the OTT CTD as
described in these operating instructions!
For further information, ➝ see Chapter 4, "Introduction".
Note all the detailed safety information given within the individual work steps.
All safety information in these operating instructions are identified with the
warning symbol shown here.
Ensure the electrical, mechanical, and climatic specifications listed in the
technical data are adhered to.
For further information ➝ see Chapter 11, "Technical data".
Handle the pressure probe cable carefully: Do not kink the cable or pull it
across sharp edges!
Do not make any changes or retrofits to the OTT CTD. If changes or retrofits
are made, all guarantee claims are voided.
Have a faulty OTT CTD inspected and repaired by our repair center. On no
account carry out repairs yourself!
For further information ➝ see Chapter 19, "Repair".
Dispose of the OTT CTD properly after taking out of service. On no account put
the OTT CTD into the normal household waste.
For further information ➝ see Chapter 20, "Notes about the disposal of old units".
Replacement
parts/
Consumable
materials

6
4 Introduction
The OTT CTD groundwater datalogger provides precise measurement and record-
ing of groundwater levels and temperatures, as well as the specific electrical
conductivity of the groundwater. The OTT CTD also calculates the salinity and a
TDS value (Total Dissolved Solids) based on the specific conductivity.
The pressure probe uses the hydrostatic pressure of the water column above a
relative pressure measuring cell to determine the water level. A pressure compen-
sation capillary in the pressure probe cable gives the measuring cell the current
ambient air pressure as a reference. Erroneous measurement results due to atmos-
pheric air pressure fluctuations are thus eliminated. The OTT CTD measures the
specific electrical conductivity using a 4-electrode conductivity sensor with inte-
grated temperature sensor. The measurement electrodes are made of graphite.
The temperature compensation process for the conductivity measurement and the
reference temperature used can be chosen as well as the calculation method for
the salinity.
The OTT CTD is available with five water level measuring ranges:
0 … 4 m water column (0 ... 0.4 bar)
0 … 10 m water column (0 ... 1 bar)
0 … 20 m water column (0 ... 2 bar)
0 … 40 m water column (0 ... 4 bar)
0 … 100 m water column (0 ... 10 bar)
With the help of a reference value that is input during startup, the OTT CTD’s
standard setting provides measurement results in the form of depth values. Alter-
natively, measured values can be levels or pressures. The measurement intervals
(sample intervals) can be preselected as necessary.
The operating parameters are adjusted with the "OTT CTD Operating program"
PC software. This software allows the system to be conveniently and flexibly
tailored to a wide range of measurement requirements. The software can be set
to provide a basic or an advanced operator interface. The basic operator inter-
face allows all settings to be adjusted within a single program window. In the
advanced operator interface, the sample interval can be controlled with limit
events, for example. The software also supports the execution of pump tests.
The stored measured values are made available through an infrared interface
(IrDA) for wireless readout by a PC with OTT CTD Operating program or OTT
Hydras 3 or by a PDA with OTT Hydras 3 Pocket.
Together with an OTT ITC intelligent top cap (accessory), remote data transfer
and remote parameter input is possible via the GSM mobile telephone network
(GSM = global system for mobile communications). The remote data transfer can
be optionally carried out by SMS text messages or using the packet oriented
mobile radio transmission service GPRS (general packet radio service).
The OTT CTD is installed simply by hanging it in observation wells of 1" in diame-
ter and larger. Various adapters/suspension brackets are available as accessories
for this purpose. Three 1.5 V lithium batteries (type AA) provide an operating life
of over five years (sample interval: 1 hour; system length: 50 m). Alternatively,
alkaline batteries with a limited working life can be used.
The communication unit of the OTT CTD can withstand temporary flooding (for
details, see chapter 21, "Technical data").

7
Top cap
Observation well
Communication unit
Pressure probe cable
Rubber stop
Pressure probe with
datalogger unit
Conductivity sensor
Pressure Sensor
DepthMeasuring range
Measuring range:
0 … 4 m, 0 … 10 m, 0 … 20 m,
0 … 40 m, 0 … 100 m water column
System length
Fig. 1: Setting up a groundwater measure-
ment station with the OTT CTD.
The OTT CTD essentially consists of three com-
ponents: Communication unit, pressure probe
cable and pressure probe with datalogger.
OTT CTD system length = length of
communication unit + cable length +
length of pressure probe with datalogger.
(The system length is required when
ordering an OTT CTD. When setting
the OTT CTD operating parameters the
system length is not required.)
(The rubber stop attached to the pressure
probe cable prevents the pipe casing from
falling when the communication unit is
open. Do not move the rubber stop!)

8
5 Installing, checking, and exchanging batteries
Please note
Only use the battery types indicated (no rechargeable batteries)!
Always use brand new batteries! Do not mix used and new batteries!
Do not mix batteries of different manufacturers!
Do not mix lithium and alkaline batteries!
Properly dispose of dead batteries! Do not include in household waste!
Suitable battery types
3 x 1.5 V AA cells (LR6/FR6),
alkaline or lithium design (LiFeS; Energizer L91)
Insert the batteries as follows
Slide the pipe casing of the communication unit approximately 30 cm in the
direction of the pressure probe cable.
Insert 3 batteries (LR6/FR6 · AA) in the battery compartment
as shown in Figure 2. Ensure that the polarity is correct!
Screw the pipe casing of the communication unit back on.
Notes
The OTT CTD begins measurements within a few seconds of the batteries being
inserted (there is no on/off switch).
If the OTT CTD is to be shut off ➝remove the batteries. This will prevent the
batteries from draining prematurely and will stop any recording of unusable
measurements.
When bringing back into operation it takes – dependent on how much data is
stored – up to 7 minutes until the OTT CTD begins measurements again.
Pipe casing
communication
unit
Battery compartment
LR6/FR6 · AA
Battery
Backstop
+
+
+
Fig. 2: Installing batteries.

9
Battery life
For a 1 hour sample interval an 50 m system length (without ITC).
Lithium batteries: at least 5 years
Alkaline batteries: at least 1.5 years (high quality battery types)
Notes
The operating program has a calculation function that determines the approxi-
mate battery life based on the operating parameters currently set. The basis for
this are lithium batteries!
Due to their design, at 0 °C, alkaline batteries drop to 50 % of their original
20 °C capacity and at –10 °C they drop to approximately 35 %. If ambient
temperatures are expected to drop below 0 °C at the measurement station, it
is recommended that lithium batteries be used.
Check the battery voltage as follows
Set up the PC/OTT CTD communication link (see Chapter 7.2).
Select the "OTT CTD" menu, "View Instantaneous values" function 1) ➝the
OTT CTD starts an instantaneous value measurement ➝the "Observer"
window indicates the current battery voltage and the energy withdrawn from
the batteries so far in Ah.
If the battery voltage is ≤ 3.6 to 3.7 volts ➝replace the batteries.
Click on the "Exit" button.
Close the operating program.
1) With suitable settings (Menu "File", Function "Options"), the operating program starts with the
"Observer" window.
Replace dead batteries as follows
Open the top cap/observation well cover.
Pull the communication unit approximately 80 cm out of the observation well
and hold (a second person would be useful).
Slide the pipe casing of the communication unit approximately 30 cm in the
direction of the pressure probe cable. (The rubber stop located on the pressure
probe cable (see Fig. 1) prevents the pipe casing from falling. Do not move the
rubber stop!)
Remove dead batteries.
Insert 3 new batteries (LR6/FR6 · AA) into the battery compartment as shown
in Figure 2 within 10 minutes. Ensure that the polarity is correct!
Slide the pipe casing of the communication unit back on until it stops.
Slowly and carefully place the communication unit back into the observation well.
Close the top cap/observation well cover.
Notes
The OTT CTD stores the measured values in a non-volatile memory. This pre-
vents any data loss when replacing the batteries. This also applies to storage
over a long time period with the batteries removed.
If it takes longer than approx. 10 minutes to replace dead batteries, the time
(and possibly the date) will have to be re-entered (see Chapter 13, "Date and
time settings"). Furthermore, it takes – dependent on how much data is stored –
up to 7 minutes until the OTT CTD begins measurements again.
When replacing the batteries, we recommend changing the desiccant capsules
at the same time (see Chapter 16.2, "Replacing the desiccant capsules").

10
6 Installing the OTT CTD
System length up to 100 meters
The installation of the OTT CTD is carried out by suspending it in the observation well.
In the process, the necessary accessories and type of installation varies depending
on the diameter of the observation well and the design of the top cap:
1" observation wells see 6.1
2", 3", 4", 5" or 6" observation wells, see 6.2
OTT top caps with recess for adapter plate
Observation wells beginning at 2" in diameter, see 6.3
top caps without recess for adapter plate
Special case: Observation wells beginning at see 6.4
2" in diameter without top cap
System length over 100 meters
For installation of an OTT CTD with a system length of more than 100 meters,
there is a special cable suspension unit available (see accessories). This suspension
unit is described separately.
Adapter plate 2"
Adapter plate 4"
Adapter plate 6"
2
3
33
3 2/3
3
1
1
2
1
Fig. 3: Installation accessory set – Part 1.
1 = hole for OTT CTD
2 = hole for contact gauge
3 = recess for screws on the top cap