Operating instructions Bubble Sensor OTT CBS

English
Operating instructions
Bubble Sensor OTT CBS
.0!
ions from 1.20
firmware vers
ith
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um
valid for instr
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 Introduction
5
4 Installing OTT CBS
7
4.1 Preparing the OTT CBS for installation
4.2 Fastening OTT CBS
4.3 Connecting measuring tube to OTT CBS
5 Installing bubble chamber
5.1 Installing bubble chamber for surface water
5.2 Installing bubble chamber for ground water
6 Connecting OTT CBS
6.1
6.2
6.3
6.4
6.5
Connect power supply
Connecting the OTT CBS to any data logger using the SDI-12 interface
Connecting the OTT CBS to any data logger using the RS-485 interface (SDI-12 / Modbus protocol)
Connecting the OTT CBS to any data logger using the 4 … 20 mA interface
Determining the maximum load resistance at the 4 … 20 mA interface
7
7
8
9
9
10
12
13
13
13
13
14
7 Activating the purge function
15
8 Adjusting operating parameters using the service interface
16
8.1
8.2
8.3
8.4
8.5
8.6
Setting the serial interface type
Setting measurement type of the 4 … 20 mA interface to level or depth measurement
Scaling the measuring range for the 4 … 20 mA interface
Setting the measuring system for the 4 … 20 mA interface
Setting measurement type of the 4 … 20 mA interface to water level or pressure measurement
Factory setting of the operating parameters
9 SDI-12 commands and responses
9.1
9.2
9.3
9.4
Overview of SDI-12 commands
Standard commands
Meta data commands
Advanced SDI-12 commands
10 Carrying out maintenance work
10.1 Activating purge function
10.2 Cleaning bubble chamber
10.3 Testing the measuring tube
16
17
17
18
18
18
19
19
21
23
24
29
29
29
29
11 "Status" LED
30
12 Note 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 – Note on the declaration of conformity
39
3
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
– 100 m
99.420.050.9.5
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
– 100 m
99.000.050.9.5
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
– hose connector 6 mm/4 mm
55.510.048.3.2
55.510.049.3.2
Straight pipe fitting
– for connecting measuring tubes with
1/8" internal diameter and 3/8" external diameter
4
63.200.025.9.2
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.
Status LED
Button for activating
the purge unit
Hose connection
for measuring tube
DIP switch compartment
Air filter for
incoming air
Terminal blocks A and B
for connecting the datalogger
and power supply
5
For the display of any error states that may occur, the OTT CBS has a "Status“
LED (see Fig. 1).
Connection to a data logger can be established via a choice of
䊳 SDI-12,
䊳 RS-485 (2-wire; SDI-12- / Modbus protocol) or
䊳 4 … 20 mA (current loop)
interface.
An additional service interface with eight-position DIP switch can be used to adjust
various operating parameters.
Fig. 2: The main layout of a level
station with OTT CBS bubble sensor.
Measuring tube
Bubble pot
EPS 50
6
Groundwater
bubble chamber
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 forwards at this point. Press the second locking device downwards and remove
the OTT CBS upwards from the top hat rail.
Fig. 3: Fastening the CBS on the top
hat rail (left)/demounting (right).
Top hat rails
Locking device
7
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.
Connection
nozzle
2.
1.
Cap nut
(wrench size: 10)
Connection nipple
Measuring tube
Ø: 2 mm
8
Measuring tube
Ø: 4 mm
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 Do 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)
Fig. 5: Routing requirements
for measuring tube.
Measuring tube
1" metal tube
Direction of flow
Bubble pot
EPS 50
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.
9
5.2 Installing bubble chamber for ground water
To install the bubble chamber for ground water, proceed as follows:
䡵 Determine 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.
Suspension cable
bubble chamber
Measuring pipe
During 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.
Cable
gland
Cover in
position B
Bubble opening
Cover in
position A
Metal pin
Hole
Bubble pot
10
䡵 As shown in Fig. 7, attach the suspension cable of the bubble chamber to the
retainer on an OTT top cap already mounted. The retaining plate allows a fine
height adjustment afterwards.
䡵 Secure the suspension cable against slipping with a knot.
䡵 If top caps without retainers are used, ensure the suspension cable is attached
securely.
䡵 Check all knots and attachments for correct position and firmness.
䡵 Lower the bubble chamber slowly into the observation well with the suspension
cable.
䡵 Feed the measuring tube out of the observation well through a hole.
Fig. 7: Installing bubble chamber for
ground water – attaching suspension cable.
Top cap
Retainer
Measuring tube
Retaining plate
Observation
well
Securing knot
Suspension cable
bubble chamber
11
6 Connecting OTT CBS
The OTT CBS has the following interfaces
䊳 SDI-12
䊳 RS-485, (2-wire; SDI-12 /Modbus protocol)
䊳 4 … 20 mA (current loop)
as well as a
䊳 connection for the power supply (UBat + GND).
The three interfaces make it possible to connect the OTT CBS both to OTT data
loggers and to any data logger by another manufacturer that has the correct
interfaces. Note that only one of the interfaces at a time can be used (no parallel
operation of interfaces).
The SDI-12 interface meets SDI-12 Standard 1.4.
All electrical connections are made using two screw terminal strips (supplied) at
terminal blocks A and B on the underside of the OTT CBS.
Fig. 8: Assignments for the screw terminal
strips A and B of the OTT CBS.
Screw terminal strip
A
B
3
4
12
1
2
3
4
RS-485 A / D+ *
RS-485 B / D– *
SDI-12 DATA
SDI-12 GND
2
+UBat
4 … 20 mA +
4 … 20 mA –
GND
1
* RS-485 interface with
SDI-12 / Modbus protocol
6.1 Connect power supply
The OTT CBS requires a power supply of 10 … 30 V DC, typ. 12/24 V DC (e.g.
using batteries or mains connection with galvanically separated low safety voltage).
Please note the following points when dimensioning the power supply:
䊳 Maximum power consumption per day: 3700 mAh (typ. 320 mAh/day) (with
1 min measurement interval and 100 m measuring tube using the 4 … 20 mA
interface)
䊳 Peak current consumption: temporary max. 2 A
䊳 Protect the supply voltage with a microfuse (e.g. 2.5 A, slow-blow)!
䊳 When using solar panels, we recommend the use of an overvoltage protection
device.
To supply the OTT CBS with power, proceed as follows:
䡵 Connect the power supply to screw terminal strip A of the OTT CBS as shown
in Fig. 8.
Notes
䊳 The OTT CBS does not have a switch for switching the unit on and off. As soon
as power is supplied, the OTT CBS is ready for operation.
䊳 Each time the power supply is attached, the piston pump operates for approx.
400 strokes (approx. 5 minutes running time).
6.2 Connecting the OTT CBS to any data logger using the SDI-12
interface
䡵 Connect the OTT CBS to an SDI-12 input of the external data logger. Follow
the data logger handbook as you do this. See Fig. 8 for the assignments. The
maximum cable length is 100 m* !
* OTT CBS connected to the data logger; no bus operation; otherwise 70 m
6.3 Connecting the OTT CBS to any data logger using the RS-485
interface (SDI-12 / Modbus protocol)
䡵 Connect the OTT CBS to an RS-485 input (SDI-12 or Modbus protocol) on the
external data logger. Refer to the data logger manual for more details. The
connection assignment can be found in Figure 8. The maximum cable length is
– SDI-12 protocol: 1000 m
– Modbus protocol: 100 m
6.4 Connecting the OTT CBS to any data logger using the
4 … 20 mA interface
䡵 Connect the OTT CBS to a 4 … 20 mA input of the external data logger.
Follow the data logger handbook as you do this as well as chapter 6.5 of these
instructions). See Fig. 8 for the assignments.
Maximum cable length: Dependent on the level of supply voltage and the load
impedance (load resistance). Make sure that the ohmic resistance of the connecting cable added to any load impedance does not exceed the maximum permitted
load resistance (see chapter 6.5 for details). In any case, the upper limit for the
cable length is 1000 m.
䡵 With depth measurement: ensure that DIP switch 4 is set to "ON".
13
6.5 Determining the maximum load resistance at the 4 … 20 mA
interface
The load resistance connected to the OTT CBS (load impedance + ohmic resistance of connecting cable) must not exceed a specific maximum value. This value
depends on the level of the supply voltage of the OTT CBS. If the load resistance is
greater, the loop current* can no longer be evaluated. Smaller load resistances
are allowed.
^ measured value)
* Current at 4 … 20 mA interface fed in (controlled) by OTT CBS (=
䡵 Read off the maximum load resistance for your power supply from the
following diagram. Alternatively, you can calculate the maximum load resistance using the following formula:
RLoad (max) = (Usupply – 7.75 V )/ 0.02275 A
Example: Power supply 18 Volt → max. load resistance 450 Ohm.
The OTT CBS delivers a loop current corresponding to the measured value for
a load resistance of up to 450 Ohm.
䡵 Dimension the connected electrical circuit accordingly. Check the input
resistance of the connected peripheral device for this purpose.
Fig. 9: Diagram to determine the
maximum load resistance as a
function of the power supply.
R
Ω
Minimum power supply: 10 V
Maximum power supply: 30 V
1000
Resistor tolerance: 0.1 %/15 ppm.
900
800
700
600
500
Example
400
300
200
100
0
10
14
15
20
25
30
U
V
7 Activating the purge function
On the front of the OTT CBS there is a "Pump" membrane button (see Fig. 10).
Pressing the button activates the purge function for as long as it is pressed. The
"Status" LED lights for approx. 2 seconds. With an activated purge function, the
CBS pumps a large amount of air through the measuring tube for the required time
period (see also chapter 11). The purge function can also be activated via an SDI12 command.
Note: Press the membrane button for at least one second as otherwise the error
memory is called and displayed at the "Status" LED.
Fig. 10: Activating purge function manually
on the OTT CBS with membrane button.
Membrane button
15
8 Adjusting operating parameters using the service
interface
The OTT CBS has a service interface with an eight-position DIP switch. This is
located behind a cover on the base of the OTT CBS (see Figure 1). The following
operating parameters can be set with them:
䊳 DIP 1, 2, 3
䊳 DIP
䊳 DIP
䊳 DIP
䊳 DIP
4
5+6
7
8
Set serial interface type (SDI-12 / RS-485)
Setting measurement type as level or depth measurement*
Scaling measuring range *
Setting metric or imperial system (m/mbar or feet/psi) *
Setting measurement type as water level or pressure
measurement *
* these settings only affect the 4 … 20 mA interface.
8.1 Setting the serial interface type
With DIP 1 … 3 select the type of SDI-12 interface of the OTT CBS (screw terminal
strip B; contacts 1 to 4). Note that only one of the interfaces at a time can be used
(4 ... 20 mA, SDI-12 or RS-485; no parallel operation of interfaces).
Fig. 11: Setting the type of SDI-12
interface of the OTT CBS.
On the RS-485 interface with termination,
there is an internal 120 Ohm terminating
resistor between the two RS-485 connections.
ON
1 2 3 4 5 6 7 8
SDI-12 interface
ON
ON
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
RS-485 interface
without termination
RS-485 interface
with termination
Possible serial interface types
䊳 SDI-12 interface (SDI-12 protocol)
䊳 RS-485 interface without termination (SDI-12 protocol / Modbus protocol)
Use this setting if multiple OTT CBS are connected in parallel to one RS-485
cable (bus operation) for all OTT CBS except the last device at the end of the
bus.
䊳 RS-485 interface with termination (SDI-12 protocol / Modbus protocol)
Use this setting if
– multiple OTT CBS are connected in parallel to the RS-485 cable
(bus operation) for the last device at the end of the bus, or if
– only one OTT CBS is connected to the RS-485 cable.
Note: When using the 4 ... 20 mA interface, the setting of DIP 1 ...3 is not relevant. (Exception: If default settings on the OTT CBS are to be changed using the
SDI-12 interface during service.)
16
8.2 Setting measurement type of the 4 … 20 mA interface to
level or depth measurement
Fig. 12: Setting measurement type level
or depth measurement of the OTT CBS
(4 … 20 mA interface).
ON
1 2 3 4 5 6 7 8
Level Measurement
ON
1 2 3 4 5 6 7 8
Depth Measurement
8.3 Scaling the measuring range for the 4 … 20 mA interface
With DIPs 5 and 6 you can scale the available measuring range (15 or 30 m) of
an OTT CBS to a smaller range. Where the whole measuring range is not required,
this has the advantage that a higher resolution for the 4 … 20 mA interface can
be achieved. Example: For 2 m water level change 16 mA measuring range is
available (DIP switches 5 + 6 = OFF).
Fig. 13: Scaling the measuring
range of the OTT CBS
(4 … 20 mA interface).
CBS version
ON
1 2 3 4 5 6 7 8
Standard +
USGS specification
30 m measuring
range
15 m / 50 ft
1.5 bar / 25 psi
(not scaled)
30 m / 100 ft
3 bar / 50 psi
(not scaled)
8 m / 25 ft
0.8 bar / 12 psi
15 m / 50 ft
1.5 bar / 25 psi
4 m / 12 ft
0.4 bar / 6 psi
8 m / 25 ft
0.8 bar / 12 psi
2 m / 6 ft
0.2 bar / 3 psi
4 m / 12 ft
1.5 bar / 6 psi
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
17
8.4 Setting the measuring system for the 4 … 20 mA interface
Fig. 14: Setting the measuring
system of the OTT CBS
(4 … 20 mA interface).
ON
1 2 3 4 5 6 7 8
Metric measurement system: m + mbar
ON
1 2 3 4 5 6 7 8
Imperial measurement system: feet + psi
8.5 Setting measurement type of the 4 … 20 mA interface to
water level or pressure measurement
Fig. 15: Setting measurement type to
water level or pressure measurement
(4 … 20 mA interface).
ON
1 2 3 4 5 6 7 8
Water level measurement
ON
1 2 3 4 5 6 7 8
Pressure measurement
8.6 Factory setting of the operating parameters
Fig. 16: Factory setting of the
operating parameters.
ON
1 2 3 4 5 6 7 8
䊳 SDI-12 interface; level measurement; measuring range not scaled; metric sys-
tem; water level measurement.
18
9 SDI-12 commands and responses
Communication with the OTT CBS is carried out using a standardised serial SDI-12 interface. In this technical documentation,
you will find a detailed description of the SDI-12 commands implemented in the SDI-12 transfer protocol.
Further information on the SDI-12 standard can be found in the document "SDI-12; A Serial-Digital Interface Standard for
Microprocessor-Based Sensors; Version 1.4" (see website "www.sdi-12.org").
All advanced, manufacturer-specific SDI-12 commands on the OTT CBS begin with "O" for OTT. With these commands it is
possible to configure the OTT CBS, for example using the "Transparent mode" on a data logger or with the OTT USB/SDI-12
interface accessory.
Conventions for measured value formats
p – Sign (+,–)
b – Figure (before decimal point); output without leading zeroes
e – Figure after the decimal point
a<CR><LF> – Service Request
!
– ends a command
9.1 Overview of SDI-12 commands
Standard commands
䊳 a!
Acknowledgement active
䊳 aI!
Send identification
䊳 aM!
Start measurement
䊳 aAb!
䊳 ?!
䊳 aD0!
䊳 aMC!
䊳 aC!
䊳 aCC!
䊳 aV!
Change sensor address
Query sensor address; factory setting: 0
Send data
Start measurement and request CRC (Cyclic Redundancy Check)
Start concurrent measurement (simultaneous measurement with multiple sensors on one bus line)
Start concurrent measurement and request CRC
Start system test
Meta data commands
䊳 aIM!
aIMC!
aIC!
aICC!
䊳 aIV!
䊳 aIM_001!
aIM_002!
aIM_003!
Determine response to associated aM!command (does not start measurement)
… aMC!
… aC!
… aCC!
Determine response to associated aV! command (does not start system test)
Query meta data for measured value 1, 2 and 3; measured value in aD0! after aM!
aIMC_001!
aIMC_002!
aIMC_003!
… aMC!
aICC_001!
aICC_002!
aICC_003!
… aCC!
aIC_001!
aIC_002!
aIC_003!
䊳 aIV_001!
… aC!
Query meta data for response to "Perform system test" command
19
Advanced commands (manufacturer-specific)
䊳 aOXM<value>!
aOXM!
䊳 aOXC<value>!
aOXC!
䊳 aOAA<value>!
aOAA!
䊳 aOAB<value>!
aOAB
䊳 aOAC<value>!
aOAC
䊳 aOXR<value>!
aOXR!
䊳 aOXT<value>!
aOXT
䊳 aOXK<value>!
aOXK!
䊳 aOXG<value>!
OXG!
䊳 aOPC<Wert>!
aOPC!
䊳 aOSU<value>!
aOSU!
䊳 aOST<value>!
aOST!
䊳 aOOV!
䊳 aOXP<value>!
䊳 aOZY<value>!
aOZY
䊳 aOPF<value>!
aOPF
䊳 aOPG<value>!
aOPG
䊳 aOPH<value>!
aOPH
20
Set measuring time
Read measuring time
Factory setting: +50 s
Set cycle time
Read cycle time
Factory setting: +60 s
Set "level" or "depth" measuring mode
Read measuring mode
Factory setting: +0 ➝ "Level" measuring mode
Set offset value for level/depth measurement (SDI-12/RS-485 interface)
Read offset
Factory setting: +0.000 m
Set reference value for level/depth measurement (SDI-12/RS-485 interface)
Read reference value
Factory setting: +0.000 m
Set mean water density
Read mean water density
Factory setting: +0.999972 kg/dm3
Set mean water temperature
Read mean water temperature
Factory setting: +3.980000 °C
Set correction factor for pressure/level value
Read correction factor for pressure/level value
Factory setting: +1.000000
Set local acceleration due to gravity
Read local acceleration due to gravity
Factory setting: +9.80665 m/s2
Set status of 4 … 20 mA interface
Read status
Factory setting: +0 ➝ 4 … 20 mA interface disabled
Set unit for level/pressure measured values
Read unit
Factory setting: +0 ➝ Unit m
Set unit for temperature measured values
Read unit
Factory setting: +0 ➝ Unit °C
Read firmware version
Activate/deactivate purge function
Factory setting: +0 ➝ Purge function deactivated
Set SDI-12 interface version
Read version
Factory setting: +1 ➝ Current version activated
Set status of Modbus protocol
Read status
Factory setting: +0 ➝ Modbus protocol deactivated
Modbus: Set bus address
Read bus address
Factory setting: +1
Modbus: Set transmission speed
Read transmission speed
Factory setting: +9600 bit/s
9.2 Standard commands
Command
a!
Response
aI!
allccccccccmmmmmm…
…vvvxxxxxx<CR><LF>
aAb!
b<CR><LF>
?!
a<CR><LF>
aM! 1)
a<CR><LF>
atttn<CR><LF>
and after 50 seconds
a<CR><LF>
aMC! 1)
atttn<CR><LF>
and after 50 seconds
a<CR><LF>
aC! 1)
atttnn<CR><LF>
aCC! 1)
atttnn<CR><LF>
1)
Description
Acknowledgement active
a – Sensor address; factory setting: 0
Send identification
a
– Sensor address
ll
– SDI-12 protocol version
cccccccc – Manufacturer identification (company name)
– Sensor designation
mmmmmm
vvv
– Sensor version (in this case Firmware version)
xxxxxxxxx – Additional designation (in this case serial
number)
OTT CBS response: 014OTT
CBS120
xxxxxx
Change sensor address
a – Old sensor address
b – New sensor address
Query sensor address
a – Sensor address
Start measurement
a
– Sensor address
ttt
– Time in seconds until the sensor
has determined the measured result
OTT CBS response: 050
n
– Number of measured values
OTT CBS response: 3
Start measurement and request CRC (Cyclic Redundancy
Check); for details see command aM!.
The response to the aD0! command is extended with a
CRC value in this case:
a<value1><value2><value3><CRC><CR><LF>
Start concurrent measurement (simultaneous measurement
with multiple sensors on one busline); for details see
command aM!.
The number of measured values in the response to this command has two digits (nn): 03.
Start concurrent measurement (simultaneous measurement
with multiple sensors on one busline) and request CRC
(Cyclic Redundancy Check); details see command aM!.
The number of measured values in the response to this
command has two digits (nn): 03.
The response to the aD0! command is extended with a
CRC value in this case:
a<value1><value2><value3><CRC><CR><LF>
Do not use these commands if the OTT CBS is connected to a data logger using the 4 … 20 mA interface. This would cause the OTT CBS to interrupt the continuous measurement mode, which is necessary for the 4 … 20 mA interface.
21
Command
aD0!*
* after
aM!, aMC!,
aC!, aCC!
Response
a,<value1>,<value2>, …
… <value3>;<CRC><CR><LF>
Description
Send data
a
<value1>
<value2>
aV!
atttn<CR><LF>
aD0!*
a<value><CR><LF>
* after aV!
22
<value3>
<CRC>
– Sensor address
– Level/depth/pressure value
Measured value formats:
m
➝ pbbbb.eee
cm
➝ pbbbbbbbb
ft
➝ pbbbbb.ee
➝ pbbb.eee
bar
mbar ➝ pbbbbbb.e
psi
➝ pbbbb.eee
– Temperature value
Measured value formats:
°C
➝ pbbb.ee
°F
➝ pbbb.ee
– Status; see command aV!
– CRC value (only after aMC!, aCC!)
Start system test
a
– Sensor address
ttt
– Time in seconds until the sensor
has determined the measured result
OTT CBS response: 001
n
– Number of measured values
OTT CBS response: 1
Send data
a – Sensor address
<value> – Status of last measurement
+0
➝ No error
+1
➝ Level too low
+2
➝ Excess pressure
+4
➝ Supply voltage too low
(< 9.6 V)
+8
➝ Overload
+16
➝ General software error
+32
➝ Motor malfunction
+64
➝ Valve malfunction
+256 ➝ Memory defective
+512 ➝ Data bus defective
+1024 ➝ Analog converter defective
+2048 ➝ Pressure measuring cell defective
9.3 Meta data commands
Command
aIM!
aIMC!
Response
aIV!
atttn<CR><LF>
aIM_001!
aIC_001!
a,<Field1>,<Field2>, …
… <Field3>;<CRC><CR><LF>
aIC!
aICC!
aIMC_001!
aICC_001!
aIM_002!
aIC_002!
aIMC_002!
aICC_002!
aIM_003!
aIC_003!
aIMC_003!
aICC_003!
1)
atttn<CR><LF>
atttn<CR><LF
atttnn<CR><LF>
atttnn<CR><LF>
a,<Field1>,<Field2>, …
… <Field3>;<CRC><CR><LF>
a,<Field1>,<Field2>, …
… <Field3>;<CRC><CR><LF>
Part of the response to the command aD0! (after aM!, aMC!, aC!, aCC!)
Description
The response is identical to the associated measuring command (aM!, aMC!, aC!, aCC!). These commands do not
start any measurements. For a description of the responses,
see commands aM!, aMC!, aC!, aCC!.
The response is identical to the associated "Start system test"
(aV!) command. This command does not start a system test!
For a description of the response, see command aV!.
The OTT CBS sends meta data for the associated measured
value <value1> 1) in the form of three data fields. These
commands do not start any measurements!
a
– Sensor address
<Field1> – Measured value code
LE (level) · DW (distance to water)
PH (hydrostatic pressure)
<Field2> – Unit
meter · cm · ft · mbar · bar · psi
<Field3> – Text description
water level · distance to water
hydrostatic pressure
<CRC>
– CRC value (only for aIMC_001!,
aICC_001!)
Examples:
0,LE,cm,water level;<CR><LF>
3,PH,mbar,hydrostatic pressure;GQa<CR><LF>
The OTT CBS sends meta data for the associated measured
value <value2> 1) in the form of three data fields. These
commands do not start any measurements!
a
– Sensor address
<Field1> – Measured value code
CU
<Field2> – Unit
degrees C · degrees F
<Field3> – Text description
average air temperature
<CRC>
– CRC value (only for aIMC_001!,
aICC_001!)
Example:
0,CU,degrees C,average air temperature;<CR><LF>
The OTT CBS sends meta data for the associated measured
value <value3> 1) in the form of three data fields. These
commands do not start any measurement!
a
– Sensor address
<Field1> – Measured value code
DS
<Field2>– Unit
(No unit, space output)
<Field3> – Text description
device status
<CRC>
– CRC value
Example:
0,DS, ,device status;<CR><LF>
23
Command
aIV_001!
Response
a,<Field1>,<Field2>, …
… <Field3>;<CR><LF>
Description
The OTT CBS sends meta data for the associated "Start system test" command (aV!) in the form of three data fields.
For a description of the meta data, see command
aIM_003!.
9.4 Advanced SDI-12 commands
Command
Response
Description
䊳 Set/read measuring time
aOXM<value>!
aOXM!
a<value><CR><LF>
a<value><CR><LF>
Set measuring time
Read measuring time
– Sensor address
a
<value> – Measuring time in seconds
pbbb
Value range:
Factory setting:
+30 … +300 s
+50 s
Duration over which the OTT CBS determines an
average measured value.
䊳 Set/read cycle time
aOXC<value>!
aOXC!
a<value><CR><LF>
a<value><CR><LF>
Set cycle time
Read cycle time
a
– Sensor address
<value> – Cycle time in seconds
pbbbb
Value range:
Factory setting:
+30 … +7200 s
+60 s
With active 4 … 20 mA interface (aOPC!➝ +1) or active
Mobus protocol (aOPF!➝ +1):
Time interval in which the OTT CBS starts measurements.
With the 4 … 20 mA interface, the OTT CBS adjusts the
loop current when the measured result is available. The condition "Cycle time ≥ Measuring time" must be met. If it is
not, the OTT CBS automatically adjusts the measuring time to
the cycle time.
䊳 Set/read level or depth measuring mode
aOAA<value>!
aOAA!
a<value><CR><LF>
a<value><CR><LF>
Set measuring mode
Read measuring mode
a
– Sensor address
<value> – +0 = "Level" measuring mode activated
(water level relative to level zero point)
+1 = "Depth" measuring mode activated
(reference point ↔ water surface)
Factory setting: +0
Please note
If entries have already been made for the "Offset" or "Reference value" parameters before changing the measuring
mode, you must reset them. There is no automatic conversion
of the parameters entered.
24
Command
Response
Description
䊳 SDI-12-/RS-485 interface – Set/read offset for level/depth measurement
aOAB<value>!
aOAB!
a<value><CR><LF>
a<value><CR><LF>
Set offset value
Read offset value
a
<value>
– Sensor address
– pbbbb.eee m *
– pbbbb cm *
– pbbbb.ee ft *
Input/output without leading zeroes.
–9999.999 … +9999.999 *
+0.000
Value range:
Factory setting:
You can use this command to apply a linear offset (positive/negative) to the level/depth measured value (basis: current measurement).
Please note
A measurement must have taken place directly before the
setting. This command overwrites any reference value set.
Example
Measured value = +10.040 m
Offset =
–0.200 m
Output =
+9.840 m
Note
If the unit is subsequently changed (aOSU<value>!) you must
reset the offset value.
䊳 SDI-12/RS-485 interface - Set/read reference value for level/depth measurement
aOAC<value>!
aOAC!
a<value><CR><LF>
a<value><CR><LF>
Set reference value
Read reference value
a
<value>
– Sensor address
– pbbbb.eee m *
– pbbbb cm *
– pbbbb.ee ft *
Input/output without leading zeroes.
Value range:
Factory setting:
–9999.999 … +9999.999 *
+0.000
You can use this command with level/depth measurement to
create a reference to a level zero point by entering a reference value (basis: current measurement).
Please note
A measurement must have taken place directly before the
setting. This command overwrites any offset value set.
Example
Measured value = +2.100 m
Reference value = +1.500 m
Output =
+1.500 m
(Offset calculated by OTT CBS and applied to all other
measured values = +0,600 m)
Note
If the unit is subsequently changed (aOSU<value>!) you must
reset the offset value
* Depends on the set unit (aOSU<value>!)
25
Command
Response
Description
䊳 Set/read average water density
aOXR<value>!
aOXR!
a<value><CR><LF>
a<value><CR><LF>
Set average water density
Read average water density
a
<value>
Value range:
Factory setting:
– Sensor address
– pb.eeeeee
+0.500000 … +2.000000 kg/dm3
+0.999972 kg/dm3 (at 3.98 °C)
You can use this command to set the actual density of the
water at your measuring point for level/depth measurement.
For example, this is useful at stations with brackish water.
䊳 Set/read average water temperature
aOXT<value>!
aOXT!
a<value><CR><LF>
a<value><CR><LF>
Set average water temperature
Read average water temperature
a
<value>
Value range:
Factory setting:
– Sensor address
– pbb.eeeeee
–20.000000 … +55.000000 °C
+3.980000 °C
You can use this command to set the actual average water
temperature at your measuring point for level/depth measurement. This is useful at measuring points with a very
low/high water temperature, for example.
䊳 Set/read correction factor for pressure/level value
aOXK<value>!
aOXK!
a<value><CR><LF>
a<value><CR><LF>
Set correction factor for pressure/level value
Read correction factor for pressure/level value
a
<value>
Value range:
Factory setting:
– Sensor address
– pb.eeeeee
+0.500000 … +2.000000
+1.000000
You can use this command to correct the pressure/level
value. The OTT CBS multiplies the measured values by the
correction factor.
䊳 Set/read local acceleration due to gravity
aOXG<value>!
aOXG!
a<value><CR><LF>
a<value><CR><LF>
Set local acceleration due to gravity
Read local acceleration due to gravity
a
<value>
Value range:
Factory setting:
– Sensor address
– pb.eeeee
+9.50000 … 9.95000 m/s2
+9.80665 m/s2
Gravity on the earth's surface fluctuates between
9.78036 m/s2 at the equator and 9.3208 m/s2 at the poles.
It also decreases by 0.003086 m/s2 for every kilometre of
altitude above sea level.
26
Command
Response
Description
Formula for local acceleration due to gravity "g" in m/s2 :
g = 9.780356 (1 + 0.0052885 sin2 α – 0.0000059 sin2 2α)
– 0.003086 h
α Latitude; h Height above sea level in km
(Source: Jursa, A.S., Ed., Handbook of Geophysics and the
Space Environment, 4th ed., Air Force Geophysics Laboratory, 1985, pp. 14-17).
Example
Local acceleration due to gravity in Kempten: At a height
above sea level of 669 m and a latitude of 47.71° the local
acceleration due to gravity is 9.80659 m/s2.
Note
The OTT CBS is preset to an average value for Germany (Kassel). The measured value variation caused by acceleration due
to gravity in Germany is ±3 mm (Flensburg – Oberstdorf). This
measured value error can be compensated by entering the
local acceleration due to gravity.
䊳 Set/read unit for level/depth/pressure measured values
aOSU<value>!
aOSU!
a<value><CR><LF>
a<value><CR><LF>
Set unit
Read unit
a
– Sensor address
<value> – Units for level/depth measurement
+0 = m; factory setting
+1 = cm
+2 = ft
The level/depth measurement is performed with
compensation for water density, average water
temperature and local acceleration due to gravity
Units for pressure measurement
+3 = mbar
+4 = bar
+5 = psi
The pressure measurement is carried out without compensation.
Please note:
If settings have already been made for the "Offset" or "Reference value" parameters before changing the unit, you
must reset them. There is no automatic conversion of the set
parameters.
䊳 Set/read unit for temperature measured values
aOST<value>!
aOST!
a<value><CR><LF>
a<value><CR><LF>
䊳 Read firmware version
aOOV!
accccccc<CR><LF>
Set unit
Read unit
a
– Sensor address
<value> – +0 = °C; factory setting
+1 = °F
Read OTT CBS firmware version
a
– Sensor address
ccccccc – Firmware version; example: V1.20.0
27
Command
Response
Description
䊳 Activate/deactivate purge function
aOXP<value>!
a<CR><LF>
Activate/deactivate purge function
a
<value>
– Sensor address
– +0 = Purge function deactivated
+1 = Purge function activated
With the purge function activated, the OTT CBS pumps a
greater volume of air through the bubble tube over a given
period. For further information, see chapter 7 and 11.1.
䊳 Set/read SDI-12 interface version
aOZY<value>!
aOZY!
a<value><CR><LF>
a<value><CR><LF>
Set version
Read version
a
<value>
– Sensor address
– +0 = Previous version active;
(up to OTT CBS firmware version
V1.15.6)
+1 = Current version active; factory setting
(up to OTT CBS firmware version
V1.20.0)
For example, the previous version of the SDI-12 interface is
required if the OTT CBS is to be fitted in an existing installation as a replacement device. This does not require a
change in the configuration of the existing data logger.
If required, you can find a description of the previous
version of the SDI-12 interface in the OTT CBS operating
manual, "04-0211".
䊳 Set/read Modbus protocol (RS-485 interface)
aOPF<value>!
aOPF!
a<value><CR><LF>
a<value><CR><LF>
Activate/deactivate Modbus protocol
Read Modbus protocol status
a
<value>
– Sensor address
– +0 = Modbus protocol deactivated;
factory setting
– +1 = Modbus protocol activated
The Modbus protocol must be activated if the OTT CBS is
connected to a programmable logic controller, for example.
䊳 Modbus: Set/read bus address (RS-485 interface)
aOPG<value>!
aOPG!
a<value><CR><LF>
a<value><CR><LF>
䊳 Modbus: Set/read transmission speed (RS-485 interface)
aOPH<value>!
aOPH!
a<value><CR><LF>
a<value><CR><LF>
Set bus address
Read bus address
a
<value>
– Sensor address
– pbbb
Value range:
+1 … +255
Factory setting: +1
Set transmission speed (Baud rate)
Read transmission speed (Baud rate)
a
<value>
– Sensor address
– +9600
+19200
Factory setting: +9600 bit/s
28
10 Carrying out maintenance work
The OTT CBS bubble sensor itself is maintenance free. We recommend that the
measuring tube and bubble chamber are checked at regular intervals as described below and cleaned as required:
10.1 Activating purge function
Activate the purge function of the OTT CBS quarterly by pressing the membrane
button "Pump" (see also Fig. 10) and checking whether air bubbles rise out of the
bubble chamber. If not, check whether the bubble chamber is blocked, and/or
whether the measuring tube is leaking or blocked.
10.2 Cleaning bubble chamber
Check the bubble chamber quarterly for sand buildup and weed infiltration. For
light sand buildup, clean the bubble chamber using the purge function, and for
heavier buildup or weed infiltration clean the bubble chamber carefully manually
(do not change the position of the bubble chamber).
10.3 Testing the measuring tube
After 15 years' operation, test the measuring tube for tightness/pressure resistance roughly every 2 years.
Never open the housing of the OTT CBS! There are no adjustment or control
elements inside the housing!
In the case of device defects, contact the OTT Repaircenter:
OTT Hydromet GmbH
Repaircenter
Ludwigstrasse 16
87437 Kempten · Germany
Phone +49 831 5617-433
Fax
+49 831 5617-439
repair@ott.com
29
11 "Status" LED
For the display of any error states that may occur, the OTT CBS has a "Status"
LED on the front of the device (see Fig. 1).
The following error states can arise:
䊳
䊳
䊳
䊳
䊳
䊳
䊳
䊳
䊳
level too low (< 5 cm)
overload (measuring range exceeded)
power supply voltage too low
pump motor overloaded
watchdog error
data memory defective
data bus defective
analog converter defective
measuring cell defective
1
2
3
4
5
6
7
8
9
x
x
x
x
x
x
x
x
x
flash
flash
flash
flash
flash
flash
flash
flash
flash
The OTT CBS shows an error state when it arises and for approximately 2 minutes
after pressing the "Pump" membrane button.
The "… defective" error states signify hardware problems that can only be rectified by the OTT Repaircenter (see chapter 10). The "watchdog error" error state
means that the OTT CBS has been restarted. No intervention is necessary.
Any error states arising can be displayed as follows:
䡵 Press "Pump" membrane button briefly (< 1 second; otherwise the purge function is called) → the LED "Status" lights once for a longer period as confirmation
→ Pause → 1st error state arising (e.g. flashing once) → Pause → 2nd error
state arising (e. g. flashing three times) → Pause → … . The OTT CBS repeats all
error states arising for approx. two minutes.
Notes
䊳 Interrupt displaying error states: press membrane button briefly.
䊳 If no error state has arisen: the LED "Status" lights once for a longer period as
confirmation.
12 Note about the disposal of old devices
In accordance with the European Union guideline 2002/96/EC, OTT takes back
old devices within the member countries of the European Union and disposes of
them in an appropriate way. The devices concerned by this are marked with the
symbol shown aside. For further information about the return procedure, please
contact your local sales contact. You will find the addresses of all sales partners in
the internet on „www.ott-hydrometry.com“. Please take into consideration also the
national implementation of the EU guideline 2002/96/EC of your country.
30
13 Technical Data
Measuring ranges
"Standard" + "USGS specification" version
"30 m measuring range" version
Resolution
Accuracy SDI-12 interface
"Standard" + "30 m measuring range" version
"USGS specification" version
Accuracy 4 … 20 mA interface
Measuring dynamics (max. level change)
Units
Interfaces
Power supply
Current consumption
Query interval 1 min
Query interval 15 min
Dimensions L x W x H
Operating/display elements
DIP switches
"Pump" membrane button
"Status" LED
Weight
Housing material
Type of protection
Temperature range
Operation
Storage
Relative humidity
Measuring tube
Internal diameter
Length
0 … 15 m or 0 … 1500 mbar
0 … 50 ft or 0 … 25 psi
0 … 30 m or 0 … 3000 mbar
0 … 100 ft or 0 … 50 psi
1 mm or 0.1 mbar
0.01 ft or 0.001 psi
±5 mm
±0.02 ft
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
±0.1 % FS; TC 10 ppm/°C (at 20 °C)
1 m/min
m or ft; bar or PSI
4 … 20 mA, SDI-12, SDI-12 via RS-485
10 … 30 VDC, typ. 12/24 VDC
typ. 320 mAh / day (max. 3 700 mAh / day)
typ. 25 mAh / day (max. 300 mAh / day)
165 mm x 205 mm x 115 mm
Setting operating parameters (eight)
Call purge function; display error status using LED
Display operating state/error status
approx. 1.500 g
ABS
IP 43
–20 … +60 °C
–40 … +85 °C
10 … 95 % not condensing
Connection possibilities for 2 mm, 4 mm, 1/8"
2 mm, 1/8": max. 100 m
4 mm: max. 75 m
31
Appendix A – Connecting the OTT CBS to OTT netDL or OTT DuoSens using the
SDI-12/RS-485 interface
Method A: Connect the OTT CBS via the SDI-12 interface (protocol and physical
interface: SDI-12). The maximum length of the cable is 70 m. Recommended cable
cross-section: 0.5 mm2:
䡵 Connect the OTT CBS as shown in Figure 17 to the OTT netDL IP data logger
or to the OTT DuoSens Compact data logger. Take note of the operating
instructions for the OTT netDL/OTT DuoSens.
Fig. 17: Connecting the OTT CBS to
OTT netDL or OTTDuoSens using the SDI-12
interface.
1
2
3
OTT DuoSens
A
SDI-12
input
4
1
2
3
SDI-12
input
4
3
4
1
2
3
4
1
B
OTT CBS
2
2
3
4
A
OTT CBS
1
1
2
3
4
B
OTT CBS
+10 … +30 V
+10 … +30 V
The letters above/below the screw terminal
strip identify the possible connections on
the OTT netDL/OTT DuoSens/CBS.
OTT netDL
C
A
OTT CBS
Method B: Connect OTT CBS using the physical RS-485 interface (SDI-12 protocol via physical RS-485 interface). The maximum length of the cable is 1.500 m.
Recommended cable type: Unshielded twisted-pair cable; recommended cable
cross-section: 0.5 mm2 (above 500 m: 0.75 mm2)
䡵 Connect the OTT CBS as shown in Figure 18 to the OTT netDL IP data logger
or to the OTT DuoSens Compact data logger. Take note of the operating
instructions for the OTT netDL/OTT DuoSens.
2
3
RS-485
input
4
1
RS-485
input
4
+10 … +30 V
1
2
3
4
1
2
3
4
A
OTT CBS
B
OTT CBS
4
1
2
3
4
B
OTT CBS
32
3
+10 … +30 V
The dotted connection is necessary if the
OTT netDL and the OTT CBS are supplied
from different voltage sources.
2
3
1
OTT DuoSens
A
2
The letters above/below the screw terminal
strip identify the possible connections on
the OTT netDL/OTT DuoSens/CBS.
OTT netDL
C
1
Fig. 18: Connecting the OTT CBS to
OTT netDL or OTT DuoSens using the
RS-485 interface (SDI-12 protocol).
A
OTT CBS
Configuring the OTT netDL/OTT DuoSens for the OTT CBS with
SDI-12 interface
䡵 Create an OTT netDL/OTT DuoSens channel with "SDI-12 Master" or
"OTT SDI RS485" function block ("Serial sensors" tab).
䡵 Apply the following settings:
Fig. 19: Adjusting the operating parameters
of the OTT netDL/OTT DuoSens "SDI-12
Master" function block.
The function block "OTT SDI RS485"
is set in the same way.
䊳 Terminal block
䊳 Slave address
䊳 Value no.
䊳 Measurement mode
䊳 Concurrent Mode*
OTT netDL "OTT SDI RS485":
C 1-2 (specified)
OTT netDL "SDI-12 Master":
C 3-4 (specified
OTT DuoSens "SDI-12 Master": A 3-4 (specified)
OTT DuoSens "OTT SDI RS485": A 1-2 (specified)
Terminal block (screw terminal strip) on the OTT netDL/
OTT DuoSens, to which the OTT CBS is connected.
SDI-12 bus address. Each slave address may
only be allocated once to an SDI-12 bus line.
(Check/set: Using the "OTT SDI-12 Interface" tool in the
operating program.) Factory setting: "0".
Indicates which measured value the OTT CBS will
record on this channel. Level/depth/pressure = 1,
Temperature = 2, Status = 3
"M!" (C!); for level/depth/pressure measured
values,temperature and status
☑: Uses instead of SDI-12 standard measuring mode
(M!) concurrent mode (C!).
This allows simultaneous measurement with multiple sensors on a bus line (the sensors respond to a measurement command without a service request). The sensors
must support version 1.2 or higher of the SDI-12 standard. Further information about Concurrent Mode can
be found in the SDI-12 standard;
see "www.sdi-12.org". This mode is useful if several
sensors with a longer measuring time and identical sample interval are connected to a bus line.
* Only in conjunction with an OTT netDL
33
䊳 Instantaneous value*
䊳 Value no./
Virtual Terminal ID
☑: For an instantaneous value request (using LCD display and jog shuttle), the OTT netDL sends a command
to start a current measurement to the OTT CBS. Until this
measurement is complete, the LCD display uses the last
measured value (or the last instantaneous value displayed if this is more recent). This is indicated by an "s"
after the channel number (sensor number) in the display. After completion of the measurement, the new
measured value appears with no additional indication.
☐: For an instantaneous value request, shows the last
measured value from the sensor (measured value from
last sample interval). This is indicated by an "s" after the
channel number (sensor number) in the display (see also
"OTT netDL IP data logger" operating manual, chapter
9.1). This setting is useful for sensors with a longer measuring time and a short sample interval.
Assignment of further measured values from the
OTT CBS – that are not recorded on this channel – to a
virtual terminal.
䡵 Set the units and the number of decimal places in the relevant "Channel"
function blocks (m: 3 · cm: 0 · ft: 2; bar: 3 · mbar: 1 · psi: 3; °C: 2 · °F: 2;
Status: 0).
Note:
䊳 Therefore, three channels on the OTT netDL/OTT DuoSens are required to record
the two measured values and the status of an OTT CBS. The first channel contains
the "SDI-12 Master" or "OTT SDI RS485" function block as the input signal. The
other channels each contain a "Virtual sensor" function block (V02 to V03) as the
input signal. Of course, it is also possible to record only individual channels. In
this case, fewer entries are necessary in the "Measured value no. / Virtual terminal no." field.
䊳 Further information on the SDI-12 commands and responses used can be found
in chapter 6 “SDI-12 commands and responses”.
Please note: The measuring time must be at least 30 seconds; the factory setting is 50 seconds.
34
Appendix B – Connecting the OTT CBS to an OTT netDL or OTT DuoSens using the
4 … 20 mA interface
䡵 Connect the OTT CBS to the OTT netDL IP data logger or to the OTT DuoSens
compact data logger as shown in Figure 20. Take note of the operating instructions for the OTT netDL/OTT DuoSens. Maximum cable length: Depending on
the level of the supply voltage and the wire cross-section used. Make sure that
the ohmic resistance of the connecting cable does not exceed the maximum
permitted load resistance (see chapter 6.5 for details). In any case, the upper
limit for the cable length is 1000 m.
Fig. 20: Connecting the OTT CBS to
OTT netDL or OTT DuoSens using a
4 … 20 mA interface.
The letters above/below the screw terminal
strip identify the possible connections on the
OTT netDL/OTT DuoSens/OTT CBS.
OTT DuoSens
C … F 3)
OTT netDL
G … K 1) / G … M 2)
1
2
3
4 … 20 mA
input
4
4 … 20 mA
input
1
2
3
4
+10 … 30 V
+10 … 30 V
In the shown application the supply of the
current loop will occur via the OTT CBS.
4
1
2
3
4
A
OTT CBS
3
3)
OTT netDL 500
OTT netDL 1000
OTT DuoSens with
analog extension only
2
2)
1
1)
A
OTT CBS
Configuring the OTT netDL/OTT DuoSens for OTT CBS with
4 … 20 mA interface
䡵 Create a OTT netDL/OTT DuoSens channel with function block "U/I/Pt100/…"
("Analog sensors" tab).
䡵 Apply the following settings:
Fig. 21: Setting operating parameters of the
OTT netDL/OTT DuoSens
"U/I/Pt100/…" function block.
䊳 Terminal block
䊳 Measuring mode
䊳 Sensor lag time (s)
OTT net DL 500 G … K
OTT netDL 1000: G ... M
OTT DuoSens:
C ... F
terminal block used (screw terminal strip)
of the OTT netDL/OTT DuoSens.
Set to "I 4-20 mA ext".
switches on the OTT netDL/OTT DuoSens
input x seconds before the actual measurement process; set to"1"
35
䊳 □ Error code if range overflow
if required: record error codes if range
overflow
䡵 Insert a function block "2-point scaling" into this channel and set the appropriate water levels for the electrical values measured (e. g. for an OTT CBS with
15 m measuring range and level measurement (DIP switches 5 + 6 = ON):
Point 1: 4 → 0; Point 2: 20 → 15). Ensure you note here the settings of DIP
switches 5 + 6!
䡵 With depth measurement: ensure that DIP switch 4 is set to ON or carry out the
inversion of the value via function "2-point scaling" (e. g. for an OTT CBS with
15 m measuring range and depth measurement (DIP switches 5 + 6 = ON):
Point 1: 4 → 15; Point 2: 20 → 0).
With the "2-point-scaling" function it is also possible to reference a level zero at
the same time.
36
Appendix C – RS-485 interface with Modbus protocol (RTU)
C.1 Prerequisites
䊳 Connection using RS-485 interface (2-wire, half duplex, with termination), see chapter 6
䊳 Service interface setting DIP 1, 2 and 3: OFF OFF ON, see chapter 8.3
䊳 Modbus protocol activated
Factory setting: deactivatet
SDI-12 command: aOPF<value>!
䊳 Bus address correctly set
Factory setting: +1
SDI-12 command: aOPG<value>!
䊳 Transmission speed correctly set
Factory setting: +9600
SDI-12 command: aOPH<value>!
C.2 "Read Holding Register" function (0x03)
Register name
Registernumber Type
Value
Factory
Setting
Accessmode
Unit
䊳 Bus address
0000
unsigned word
1 … 247
1
R/W
–
䊳 Baud rate
0001
unsigned word
9600 · 19200
9600
R/W
Bit/s
䊳 Parity
0002
unsigned word
0 …2
0
R/W
–
0 ➝ None
1 ➝ Odd
2 ➝ Even
䊳 Serial number
0003
unsigned word
10 Byte; ASCII-Format
–
R
–
䊳 Firmware version
0008
unsigned word
10 Byte; ASCII-Format
–
R
–
䊳 Cycle time
0013
unsigned word
30 … 7200
60
R/W
s
䊳 Level/pressure/
0014
unsigned word
0…5
0
R/W
0
1
2
3
4
5
䊳 Temperature mea-
0015
unsigned word
0 …1
0
R/W
0 ➝ °C
1 ➝ °F
䊳 Level/depth
0016
unsigned word
0 …1
R/W
–
measured value unit
sured value unit
measuring mode
➝
➝
➝
➝
➝
➝
m
cm
ft
mbar
bar
psi
0 ➝ Depth
1 ➝ Level
䊳 Local acceleration
0018
float 1)
9.50000 … 9.95000
9.80665
R/W
m/s2
䊳 Mean water
0020
float 1)
–20.00 … +55.00
+3.98
R/W
°C
䊳 Mean water density
0022
float 1)
0.500000 … 2.000000
0.999972
R/W
kg/dm3
䊳 Level/depth measure- 0024
float 1)
–9999.999 … +9999.999 0.000
R/W
m · cm · ft
䊳 Level/depth measure- 0026
float 1)
–9999.999 … +9999.999 0.000
R/W
m · cm · ft
due to gravity
temperature
ment offset value
ment reference value
1)
Byte-sequence: CD AB (Big Endian – Word Swap)
37
C.3 "Read Input Register" function (0x04)
Register name
Type
Access mode
Unit
Level/depth/pressure measured value 0000
float 1)
R
m · cm · ft
mbar · bar · psi 2)
Temperature measured value
0002
float 1)
R
°C · °F 1)
Status of last measurement 3)
0004
float 1)
R
–
Operating hours
0006
float 1)
R
–
1)
2)
3)
Register number
Byte sequence: CD AB (Big Endian – Word Swap)
Depending on the set unit; see function "Read Holding Register" (0x03), register number 0014 and 0015
For a description of the potential output values, see chapter 9.2, SDI-12 command aD0! after aV!
38
Appendix D – Note on the declaration of conformity
If required, you can download the current version of the declaration of conformity
for the OTT CBS from our website as a PDF file: "www.ott.com/resources".
39
OTT Hydromet GmbH
Document number
63.200.001.B.E 05-0517
Ludwigstrasse 16
87437 Kempten ⋅ Germany
Phone +49 831 5617-0
Fax
+49 831 5617-2 09
info@ott.com · www.ott.com