OTT CBS Manuale utente
English
Operating instructions
Bubble Sensor OTT CBS
valid for instruments with firmware versions from 1.20.0!
We reserve the right to make technical changes and improvements without notice.
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Table of Contents
1 Scope of supply 4
2 Order numbers 4
3 Introduction 5
4 Installing OTT CBS 7
4.1 Preparing the OTT CBS for installation 7
4.2 Fastening OTT CBS 7
4.3 Connecting measuring tube to OTT CBS 8
5 Installing bubble chamber 9
5.1 Installing bubble chamber for surface water 9
5.2 Installing bubble chamber for ground water 10
6 Connecting OTT CBS 12
6.1 Connect power supply 13
6.2 Connecting the OTT CBS to any data logger using the S I-12 interface 13
6.3 Connecting the OTT CBS to any data logger using the RS-485 interface (S I-12 / Modbus protocol) 13
6.4 Connecting the OTT CBS to any data logger using the 4 … 20 mA interface 13
6.5 etermining the maximum load resistance at the 4 … 20 mA interface 14
7 Activating the purge function 15
8 Adjusting operating parameters using the service interface 16
8.1 Setting the serial interface type 16
8.2 Setting measurement type of the 4 … 20 mA interface to level or depth measurement 17
8.3 Scaling the measuring range for the 4 … 20 mA interface 17
8.4 Setting the measuring system for the 4 … 20 mA interface 18
8.5 Setting measurement type of the 4 … 20 mA interface to water level or pressure measurement 18
8.6 Factory setting of the operating parameters 18
9 SDI-12 commands and responses 19
9.1 Overview of S I-12 commands 19
9.2 Standard commands 21
9.3 Meta data commands 23
9.4 Advanced S I-12 commands 24
10 Carrying out maintenance work 29
10.1 Activating purge function 29
10.2 Cleaning bubble chamber 29
10.3 Testing the measuring tube 29
11 "Status" LED 30
12 ote about the disposal of old devices 30
13 Technical Data 31
Appendix A – Connecting the OTT CBS to OTT netDL or
OTT DuoSens using the SDI-12/RS-485 interface 32
Appendix B – Connecting the OTT CBS to an OTT netDL or
OTT DuoSens using the 4 … 20 mA interface 35
Appendix C – RS-485 interface with Modbus protocol (RTU) 37
Appendix D – ote on the declaration of conformity 39
1 Scope of supply
䊳 OTT CBS –1 Bubble Sensor OTT CBS with possibility for connecting measuring tubes with
4 mm/2 mm external/internal diameter
–1 Installation kit (top hat rail with fastening parts; screw terminal blocks,
pin jumpers)
–1 Operating Instructions
–1 Factory acceptance test (FAT) certificate
2 Order numbers
䊳 OTT CBS Bubble Sensor OTT CBS 63.200.001.9.2
䊳Accessories Measuring tube
4 mm/2 mm external/internal diameter; transparent PE
– 50 m 99.420.050.9.5
– 100 m 99.420.100.9.5
Combined measuring tube/
bubble chamber suspension cable
black, with kevlar core for length stabilization, measuring tube
with 4 mm/2 mm external/internal diameter; transparent PE
– 50 m 99.420.009.9.5
– 100 m 99.420.008.9.5
Measuring tube
6 mm/4 mm with sheathing
Length as requested 20.500.133.5.5
Measuring tube
6 mm/4 mm without sheathing
Length as requested 20.500.302.5.5
Bubble chamber suspension cable
black, with Kevlar core for length stabilization
– 50 m 99.000.050.9.5
– 100 m 99.000.100.9.5
Bubble chamber for ground water
– for observation wells beginning at 2" diameter, 670 gram 55.510.051.4.2
Bubble Pot EPS 50 for surface water
– hose connector 4 mm/2 mm 55.510.048.3.2
– hose connector 6 mm/4 mm 55.510.049.3.2
Straight pipe fitting
– for connecting measuring tubes with 63.200.025.9.2
1/8" internal diameter and 3/8" external diameter
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3 Introduction
The OTT CBS, working on the air bubble principle, can be used for measuring
ground water or water levels depending on the bubble chamber used.
To meet the various demands of the station, three different versions of the
OTT CBS bubble sensor are available:
"Standard" version:
䊳Measuring range 0 … 15 m or 0 … 1500 mbar
䊳Resolution 1 mm or 0.1 mbar
䊳Accuracy ±5 mm
"USGS specification" version:
䊳Measuring range 0 … 15 m or 0 … 1500 mbar
䊳Resolution 1 mm or 0.1 mbar
䊳Accuracy measuring range 0 … 15 ft: ±0.01 ft
measuring range 15 … 50 ft: ±0.065 % of measured
value or ±0.02 ft, whichever is less
"30 m measuring range" version:
䊳Measuring range 0 … 30 m or 0 … 3000 mbar
䊳Resolution 1 mm or 0.1 mbar
䊳Accuracy ±5 mm
The compressed air produced by a piston pump flows via a measuring tube and
the bubble chamber into the water to be measured. The pressure created in the
measuring tube is directly proportional to the water column above the bubble
chamber. The OTT CBS determines the barometric air and bubble pressure one
after the other. By taking the difference between the two signals, the OTT CBS
calculates the height of the water level above the bubble chamber.
The power supply can be provided from a mains adapter, battery or solar power.
The OTT CBS contains a purge function. This clears the measuring tube and the
bubble chamber of any minor contamination by pumping a large volume of air
into the measuring tube.
By using an intelligent pump strategy, no air drying unit is necessary for the
measuring range of 0 … 15 m.
Fig. 1: Overview of OTT CBS.
Hose connection
for measuring tube
Air filter for
incoming air
DIP switch compartment
Status LED
Button for activating
the purge unit
Terminal blocks A and B
for connecting the datalogger
and power supply
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For the display of any error states that may occur, the OTT CBS has a "Status“
LE (see Fig. 1).
Connection to a data logger can be established via a choice of
䊳 S I-12,
䊳 RS-485 (2-wire; S I-12-/Modbus protocol) or
䊳 4 … 20 mA (current loop)
interface.
An additional service interface with eight-position IP switch can be used to adjust
various operating parameters.
Bubble pot
EPS 50
Groundwater
bubble chamber
Measuring tube
Fig. 2: The main layout of a level
station with OTT CBS bubble sensor.
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4 Installing OTT CBS
4.1 Preparing the OTT CBS for installation
䡵 If required and not yet completed: Adjust operating parameters using service
interface (see chapter 8).
4.2 Fastening OTT CBS
The OTT CBS is designed only to be installed on top hat rails (a section of top hat
rail is supplied with the OTT CBS). Choose a dry and dust free location for the
installation such as a gage station or control cabinet.
䡵 First attach the OTT CBS on the upper edge of the top hat rail and then press
the underside against the top hat rail until it clicks into place.
Demounting OTT CBS
䡵 First press one locking device downwards and pull the OTT CBS slightly for-
wards at this point. Press the second locking device downwards and remove
the OTT CBS upwards from the top hat rail.
Top hat rails Locking device
Fig. 3: Fastening the CBS on the top
hat rail (left)/demounting (right).
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4.3 Connecting measuring tube to OTT CBS
To install the measuring tube on the OTT CBS, proceed as follows:
Measuring tube with 2 mm internal diameter
䡵 Cut off the end of the measuring tube square with a sharp knife and push onto
the factory fitted connection nipple.
Maximum length of the measuring tube: 100 m.
Measuring tube with 4 mm internal diameter
䡵 Cut off the end of the measuring tube square with a sharp knife.
䡵 Remove cap nut (width across flats: 10) and pull off the (short) factory mounted
measuring tube from the connection nozzle.
䡵 Push cap nut over the measuring tube (Ø 4 mm).
䡵 Push measuring tube onto the connection nozzle.
䡵 Push the cap nut back onto the connection nozzle and tighten by hand.
Maximum length of the measuring tube: 75 m.
Measuring tube with 1/8" internal diameter
A special pipe fitting for the 1/8" internal diameter measuring tube is available
(accessory). Please follow the instructions delivered with the pipe fitting for
installing the pipe.
Maximum length of the measuring tube: 100 m.
Fig. 4: Connecting measuring
tube on OTT CBS.
Cap nut
(wrench size: 10)
Connection
nozzle
Measuring tube
Ø: 4 mm
1.
2.
Connection nipple
Measuring tube
Ø: 2 mm
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5 Installing bubble chamber
Please ensure the following points are noted during installation:
䊳 No contamination or moisture may be allowed into the measuring tube.
䊳When immersing the bubble chamber (only EPS 50), the OTT CBS must be
activated, so that the piston pump is operating during this process.
䊳o not damage or kink the measuring tube during installation.
䊳Lay the measuring tube such that there is a continuous drop from the OTT CBS
towards the bubble chamber. Otherwise moisture could collect in a "hollow"
and potentially block the tube with the formation of drops (see Fig. 5)
5.1 Installing bubble chamber for surface water
We recommend using the Bubble Pot EPS 50 for measurements in surface waters.
See "Bubble Pot EPS 50" installation instructions for information on its installation.
Fig. 5: Routing requirements
for measuring tube.
1" metal tube
Direction of flow
Bubble pot
EPS 50
Measuring tube
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5.2 Installing bubble chamber for ground water
To install the bubble chamber for ground water, proceed as follows:
䡵 etermine depth of the bubble chamber (e.g. using a contact gauge). The
bubble chamber must be positioned under the lowest expected water level.
Depth = distance from bubble opening to upper edge of the
top cap
䡵 Push the measuring tube into the cable gland of the bubble chamber as far as
it goes.
䡵 Tighten the cable gland firmly by hand
䡵 Cut suspension cable to length; suspension cable length = depth +
125 cm (to protect the suspension cable from being twisted off, it can be
melted, with a cigarette lighter for example).
䡵 Feed the suspension cable through the hole in the bubble chamber as shown in
figure 6 and tie firmly.
䡵 Slide cover into position B (upwards), see Fig. 6.
Fig. 6: Installing bubble
chamber for ground water.
When lowering the bubble chamber, the
cover must be in position B! The cover
prevents water entering the measuring
tube during installation.
uring initial startup, over pressure builds
up in the measuring tube. As a result, the
cover falls back to position A and opens the
measuring tube in the process.
Measuring pipe
Suspension cable
bubble chamber
Metal pin
Cover in
position A
Bubble opening Cover in
position B
Cable
gland
Hole
Bubble pot
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