Campbell CS451 User manual

Revision: 10/2020
Copyright © 2009 – 2020
Campbell Scientific, Inc.

Table of contents
1. Introduction 1
2. Precautions 1
3. Initial inspection 2
4. QuickStart 2
5. Overview 5
6. Specifications 7
7. Installation 9
7.1 Installation considerations 9
7.1.1 Vent tube 9
7.1.2 Appropriate water depth 10
7.1.3 Dislodge bubbles 10
7.2 Installing and securing the transducer 11
7.2.1 Split mesh cable grip 11
7.2.2 Heyco cable grip 12
7.3 Wiring 12
7.3.1 SDI-12 data logger connections 13
7.3.2 RS-232 connections 13
7.4 Programming 13
7.4.1 SDI-12 programming 14
7.4.2 Offset calculation 14
7.5 Changing nose cones 15
8. Operation 16
8.1 Configuration 16
8.1.1 Computer connection using the A200 16
8.1.1.1 Driver installation 16
8.1.1.2 A200 wiring 17
8.1.1.3 Powering the sensor 17
8.1.1.4 Determining which COM port the A200 has been assigned 18
8.1.2 Device Configuration Utility (version 2.03 or higher) 18
Table of Contents - i

8.2 SDI-12 commands 19
8.3 Measuring multiple SDI-12 sensors 22
8.4 Unit command 22
8.5 Sample number command 23
9. Maintenance 23
9.1 Every visit 24
9.2 Every two years 24
10. Troubleshooting 25
Appendix A. Importing Short Cut code into CRBasic Editor 26
Appendix B. Example program 27
Appendix C. Calibration certificate 29
Appendix D. SDI-12 sensor support 30
D.1 SDI-12 command basics 30
D.1.1 Acknowledge active command (a!) 31
D.1.2 Send identification command (al!) 31
D.1.3 Start verification command (aV!) 32
D.1.4 Address query command (?!) 32
D.1.5 Change address command (aAb!) 32
D.1.6 Start measurement commands (aM!) 33
D.1.7 Start concurrent measurement commands (aC!) 33
D.1.8 Start measurement commands with cyclic redundancy check (aMC! and aCC!) 35
D.1.9 Stopping a measurement command 35
D.1.10 Send data command (aD0! … aD9!) 35
D.1.11 Extended commands 36
D.2 SDI-12 transparent mode 36
D.2.1 Changing an SDI-12 address 37
D.2.2 Changing an SDI-12 address — CR200(X) Series 38
D.3 References 39
Appendix E. RS-232 connection via computer terminal software 40
Table of Contents - ii

1. Introduction
The CS451/CS456 Submersible Pressure Transducer provides pressure and temperature
measurements. It uses the SDI-12 or RS-232 communications protocols to communicate with an
SDI-12 or RS-232 recorder simplifying installation and programming.
NOTE:
This manual provides information only for CRBasic data loggers. For retired Edlog data logger
support, access a retired manual at www.campbellsci.com/old-manuals.
2. Precautions
lREAD AND UNDERSTAND the Safety section at the back of this manual.
lSensor will be damaged if it is encased in frozen liquid.
lAlthough the CS451/CS456 is rugged, it is also a highly precise scientific instrument and
should be handled as such. There are no user-serviceable parts and any attempt to
disassemble the device will void the warranty.
lDropping the instrument or allowing it to “free fall” down a well may damage the
transducer.
lNever suspend the CS451/CS456 from the connections at the top end of the cable. Sharp
bends or excessive pinching of the cable can cause damage and may pinch off the vent
tube causing measurement errors.
lConfirm the compatibility of the sensor and cable to non-water environments before
installation.
lThe CS456, instead of the CS451, should be used in harsh water applications, including salt
water.
CS451/CS456 Submersible Water-Level Recording Sensor 1

3. Initial inspection
lUpon receipt of the CS451/CS456, inspect the packaging for any signs of shipping damage
and, if found, report the damage to the carrier in accordance with policy. Also inspect the
contents of the package and file a claim if shipping related damage is discovered.
lThe model number and pressure range is etched on the housing, and the cable length is
printed on the label near the connection end of the cable. Check this information against
the shipping documentation to ensure that the expected product was received.
lEnsure the desiccant tube is attached to the vent tube on the cable. Desiccant should be
orange or blue. Replace it if the desiccant is green or pale pink.
4. QuickStart
A video that describes data logger programming using Short Cut is available at:
www.campbellsci.com/videos/cr1000x-datalogger-getting-started-program-part-3. Short Cut is
an easy way to program your data logger to measure the sensor and assign data logger wiring
terminals. Short Cut is available as a download on www.campbellsci.com. It is included in
installations of LoggerNet, RTDAQ, PC400, or PC200W.
The following procedure also describes programming with Short Cut.
1. Open Short Cut and click Create New Program.
2. Double-click the data logger model.
CS451/CS456 Submersible Water-Level Recording Sensor 2

3. In the Available Sensors and Devices box, type CS451 or locate the sensor in the Sensors >
Water >Level & Flow folder. Double-click CS450/CS451/CS455/CS456 Pressure
Transducer. Water level defaults to feet and temperature defaults to degrees Celsius. These
can be changed by clicking the Water Level or Temperature box and selecting a different
option. Type the correct SDI-12 Address for the CS451.
4. Click on the Wiring tab to see how the sensor is to be wired to the data logger. Click OK
after wiring the sensor.
CS451/CS456 Submersible Water-Level Recording Sensor 3

5. In the Available Sensors and Devices box, type Offset and double-click the Offset
Calculation under the Sensors >Water >Level & Flow folder. For the Linked Level
parameter, select the variable that stores the level measurement (typically Lvl_ft or Lvl_m).
Type the initial water level in the Observed Level Reading box.
6. Repeat steps three and four for other sensors being measured. Click Next.
7. In Output Setup, type the scan rate, Data Output Storage Intervals, and meaningful table
names.
CS451/CS456 Submersible Water-Level Recording Sensor 4

8. Select the measurement and its associated output options.
9. Click Finish and save the program. Send the program to the data logger if the data logger
is connected to the computer.
10. If the sensor is connected to the data logger, check the output of the sensor in the data
logger support software data display in LoggerNet, RTDAQ, PC400, or PC200W to make
sure it is making reasonable measurements.
5. Overview
The CS451/CS456 pressure transducer provides a reliable, accurate pressure/level measurement
that is fully temperature compensated. Its 24-bit A/D has simultaneous 50/60 Hz rejection and
automatic calibration for each measurement.
A number of additional advanced measurement techniques are employed to harness the best
possible performance available from today’s state-of-the-art pressure transducer technology. The
transducer reverts to a low power sleep state between measurements. A series of measurements
are performed yielding a temperature and pressure value. This measurement cycle takes less than
1.5 s. The transducer can also be configured to output pressure only in less than 1 s. The
measurement cycle is activated using SDI-12 or RS-232 commands.
The transducer consists of a piezoresistive sensor housed in a 316L stainless-steel (CS451) or
titanium (CS456) package to enhance reliability. The rugged construction makes the
CS451/CS456 suitable for water level measurement in irrigation applications, water wells, lakes,
CS451/CS456 Submersible Water-Level Recording Sensor 5

streams, and tanks. The titanium package of the CS456 makes it ideal for salt water or other
harsh environments. The cable incorporates a vent tube to compensate for atmospheric pressure
fluctuations and the jacket is made of rugged Hytrel®, designed to remain flexible and tough,
even under harsh environmental conditions.
The CS451/CS456 has two communication options: SDI-12 and RS-232. The CS451/CS456 is
shipped from the factory with both communications options enabled. As an SDI-12 sensor, the
CS451/CS456 is shipped with an address of 0.
Two values are output by the CS451/CS456—pressure/level and temperature. By default, the
sensor outputs pressure in pounds per square inch gage (psig), which is the pressure relative to
atmospheric pressure. By default, the sensor outputs temperature in degrees Celsius.
The CS451/CS456 has three nose cone options. FIGURE 5-1 (p. 6) shows the nose cone options.
The weighted nose cone makes the transducer easier to submerge to depth. The 1/4-inch NPT
nose cone allows the transducer to be used in closed-pipe applications. Nose cones can be
switched out later. The nose cones are available separately from Campbell Scientific, allowing the
nose cone to be changed to a different style at a later date, if desired.
FIGURE 5-1. CS451 nose cone options
Features:
lOutput acceptable for recording devices with SDI-12 or RS-232 capability including
Campbell Scientific data loggers
lQuality construction ensures product reliability
CS451/CS456 Submersible Water-Level Recording Sensor 6

lRugged stainless steel or titanium case protects piezoresistive sensor
lFully temperature compensated
lLow power sleep state between measurements reduces power consumption
lWeighted nose cone offered adds 0.2 kg (7.4 oz) to the transducer weight. Additional
weight makes submersion of the transducer easier
lCompatible with Campbell Scientific CRBasic data loggers: CR6, CR3000, CR1000X, CR800
series, CR300 series, CR1000
6. Specifications
Power requirements: 5 to 18 VDC
Power consumption
Idle current: < 50 µA
Measurement/communication current: 8 mA for 1-s measurement
Maximum peak current: 40 mA
Measurement time: Less than 1.5 s
Outputs: SDI-12 (version 1.3) 1200 bps
RS-232 9600 bps, 8 data bits, no parity, 1 stop bit, no
flow control
Measurement ranges:
Pressure (psig) Pressure (kPa) Depth of fresh water
0 to 2.9 0 to 20 0 to 2 m (6.7 ft)
0 to 7.25 0 to 50 0 to 5.1 m (16.7 ft)
0 to 14.5 0 to 100 0 to 10.2 m (33.4 ft)
0 to 29 0 to 200 0 to 20.4 m (67 ft)
0 to 72.5 0 to 500 0 to 50.9 m (167 ft)
0 to 145 0 to 1000 0 to 102 m (334.5 ft)
Accuracy: ±0.1% full scale range TEB1or
±0.05% full scale range TEB2
Water-level resolution: 0.0035% full scale range
CS451/CS456 Submersible Water-Level Recording Sensor 7

Worst-case temperature resolution: 0.006 °C
Overpressure: Twice the pressure range
Dry storage temperature: –40 to 100 °C
CAUTION:
Sensor will be damaged if it is encased in frozen liquid.
Operating temperature: 0 to 60 °C
Temperature accuracy: ±0.2 °C
Maximum cable length
SDI-12 (one transducer connected to a
single terminal): ~475 m (1500 ft)
SDI-12 (10 transducers connected to a
single terminal3): 60 m (200 ft)
RS-232: 60 m (200 ft)
Cable type: 5 Conductor, 26 AWG
Hytrel jacket
Body material: CS451 – 316L stainless steel
CS456 – titanium
Element material: CS451 – 316L stainless steel
CS456 – Hastelloy
Standard nose cone material: Delrin
Length: 213.36 mm (6.875 in)
Diameter: 21.34 mm (0.84 in)
Cable outer diameter: 0.589 cm (0.232 in) nominal
0.599 cm (0.236 in) maximum
Distance from pressure sensor interface
(black line etched on housing) to:
End of NPT fitting: 2.54 cm (1 in)
End of standard nose cone: 2.3 cm (0.9 in)
End of weighted nose cone: 9.9 cm (3.9 in)
CS451/CS456 Submersible Water-Level Recording Sensor 8

Air gap
Standard and weighted nose cone: 0.653 cm (0.257 in)
NPT fitting: 2.72 cm (1.07 in)
Weight:
CS451: 0.17 kg (0.37 lb)
CS456: 0.10 kg (0.23 lb)
Cable: 0.421 kg/m (0.283 lb/ft)
Compliance: View the EU Declaration of Conformity at:
www.campbellsci.com/cs451
www.campbellsci.com/cs456
1Total Error Band (TEB) includes the combined errors due to nonlinearity, hysteresis, nonrepeatability, and thermal
effects over the compensated temperature range, per ISA S51.1.
20.05% full scale range accuracy not available in the 0 to 2.9 psig range.
3Campbell Scientific recommends using separate terminals when possible.
7. Installation
If using Short Cut to program the data logger, skip Wiring (p. 12) and Programming (p. 13). Short
Cut automatically performs these steps. See QuickStart (p. 2) for a Short Cut tutorial.
7.1 Installation considerations
The CS451/CS456 is designed for water level measurements. Typical applications include
agricultural water level/flow, water wells, lakes, streams, and tanks. If the device is to be installed
in a liquid other than water or in contaminated water, check the compatibility of the wetted
material. The CS456 should be used in harsh water applications, including salt water.
7.1.1 Vent tube
A vent tube incorporated in the cable vents the sensor diaphragm to the atmosphere. This
eliminates the need to compensate for changes in barometric pressure. To prevent water vapor
from entering the inner cavity of the sensor, the vent tube opening terminates inside a desiccant
tube.
CS451/CS456 Submersible Water-Level Recording Sensor 9

CAUTION:
The desiccant tube is shipped with a black cap to cover the vent hole. This cap MUST be
removed prior to installation.
Before installing the sensor, check the desiccant and replace it if the desiccant is green instead of
orange.
NOTE:
Until August 2019, the CS451/CS456 used blue desiccant that turned pink when it became
saturated.
The desiccant tube must always be attached to the CS451/CS456.
7.1.2 Appropriate water depth
The CS451/CS456 must be installed below the water at a fixed depth. This depth should be
chosen so that the water pressure will never exceed the transducer’s pressure range (twice its
pressure rating).
CAUTION:
The output reading will not be correct, and the transducer can be damaged if pressure is
twice its pressure rating.
Pressure can be converted to feet of fresh water using the following conversion:
1 psi = 2.31 feet of water
For example, the maximum depth with a pressure range of 0 to 7.25 psig is 16.748 feet of water.
7.1.3 Dislodge bubbles
While submersing the CS451/CS456, air bubbles may become trapped inside the nose cone,
causing small, offset errors until the bubbles dissolve. Dislodge these bubbles by gently shaking
the CS451/CS456 while under water.
CAUTION:
Hitting the instrument against the well casing or other solid surface could damage the
CS451/CS456.
CAUTION:
If the bubbles are not removed by rotation and shaking underwater (or bleeding out the air
in a closed system), the CS451/CS456 reading will drift lower by the distance of the gap as the
air is slowly dissolved into the water over time.
CS451/CS456 Submersible Water-Level Recording Sensor 10

7.2 Installing and securing the transducer
Lower the transducer to an appropriate depth. With long drops, it may be necessary to use the
weighted nose cone (option -WN).
CAUTION:
Do not drop the instrument or allow it to free fall down a well as this may damage the sensor.
Secure the body using cable ties or tape. A Heyco cable grip can also be used to secure the
transducer to a PVC pipe; see Heyco cable grip (p. 12) for more information. Secure and strain
relief the cable using cable ties or the split mesh cable grip. If installing in a well, fasten the cable
to the well head.
CAUTION:
Never suspend the CS451/CS456 from the connections at the top of the cable. Sharp bends
or excessive pinching of the cable can cause damage and may pinch off the vent tube
causing measurement errors.
After installation, take several readings to ensure proper operation.
7.2.1 Split mesh cable grip
The split mesh cable grip can be used to center the cable and to provide a method of suspending
the cable-reducing cable stretch. It is often recommended for use in wells. FIGURE 7-1 (p. 11)
shows a transducer cable suspended using the split mesh cable grip.
FIGURE 7-1. Transducer suspended with split mesh cable grip
CS451/CS456 Submersible Water-Level Recording Sensor 11

7.2.2 Heyco cable grip
To protect your transducer during deployment, Campbell Scientific offers the Heyco cable grip
(FIGURE 7-2 (p. 12)) to clamp the transducer to the submerged end of a 1-inch PVC pipe (FIGURE
7-3 (p. 12)). The PVC pipe will help protect the sensor and cable from debris and disturbances
while also providing a more secure means of anchoring the sensor to minimize movement. The
Heyco fitting is not meant to be water tight and water will likely fill the submerged pipe behind
the fitting. A 1-inch female adapter socket with FPT threads is needed between the Heyco cable
grip and 1-inch PVC pipe. This adapter socket is available at any store that sells PVC pipe.
FIGURE 7-2. Heyco Cable Grip
FIGURE 7-3. Transducer mounted in PVC pipe using the Heyco cable grip
7.3 Wiring
NOTE:
Power down the system before wiring the CS451/CS456.
CS451/CS456 Submersible Water-Level Recording Sensor 12

7.3.1 SDI-12 data logger connections
Table 7-1: Wire color, function, and data logger connection for SDI-12 measurements
Wire color Wire function Data logger connection
White SDI-12 signal Cterminal or Uconfigured for SDI-121
Clear Shield ⏚(analog ground)
Red Power 12V,Battery+
Black Power ground G
Blue Ground ⏚(analog ground)
Yellow Ground ⏚(analog ground)
1Uterminals are automatically configured by the measurement instruction.
For the CR6 and CR1000X data loggers, triggering conflicts may occur when a companion
terminal is used for a triggering instruction such as TimerInput(),PulseCount(), or
WaitDigTrig(). For example, if the CS451 is connected to C3 on a CR1000X, C4 cannot be
used in the TimerInput(),PulseCount(), or WaitDigTrig() instructions.
7.3.2 RS-232 connections
Table 7-2: Wire color, function, data logger connection, and RS-232 pin
Wire color CS451/CS456 function Data logger connection RS-232 9-pin
Red +12vdc 12V,Battery+
Black Power ground G
White RS-232 Tx (output) Odd-numbered Cterminal Pin 2 Rx (input)
Blue RS-232 Rx (input) Even-numbered Cterminal Pin 3 Tx (output)
Yellow Digital ground ⏚(analog ground) Pin 5 GND
Clear Shield GND ⏚(analog ground)
7.4 Programming
Short Cut is the best source for up-to-date data logger programming code.
If data acquisition requirements are simple, a data logger program can probably be created and
maintained exclusively with Short Cut. If your data acquisition needs are more complex, the files
CS451/CS456 Submersible Water-Level Recording Sensor 13

that Short Cut creates are a great source for programming code to start a new program or add to
an existing custom program.
NOTE:
Short Cut cannot edit programs after they are imported and edited in CRBasic Editor.
A Short Cut tutorial is available in QuickStart (p. 2). To import Short Cut code into CRBasic Editor
to create or add to a customized program, follow the procedure in Importing Short Cut code into
CRBasic Editor (p. 26). Programming basics for CRBasic data loggers are provided in the
following sections. A complete program example for the CR1000X data logger can be found in
Example program (p. 27). Programming basics and programming examples for Edlog data
loggers are provided at www.campbellsci.com\old-manuals.
7.4.1 SDI-12 programming
The SDI12Recorder() instruction is used to measure a CS451/CS456 configured for SDI-12
measurements. This instruction sends a request to the sensor to make a measurement and then
retrieves the measurement from the sensor. See SDI-12 commands (p. 19) for more information.
For most data loggers, the SDI12Recorder() instruction has the following syntax:
SDI12Recorder(Destination, SDIPort, SDIAddress, “SDICommand”, Multiplier,
Offset, FillNAN, WaitonTimeout)
For the SDIAddress, alphabetical characters need to be enclosed in quotes (for example, “A”).
Also enclose the SDICommand in quotes as shown. The Destination parameter must be an
array. The required number of values in the array depends on the command (see Table 8-3 (p.
20)).
FillNAN and WaitonTimeout are optional parameters (refer to CRBasic Help for more
information).
7.4.2 Offset calculation
The pressure created is directly proportional to the water column above the sensor. An offset is
used to correct the final measurement to any error due to sensor zero offset or installation. The
steps for calculating the offset:
1. Use a staff gage (or other device) to measure the initial elevation of water.
2. Measure the water pressure using the CS451/CS456.
3. Convert the pressure measurement to water level.
4. Subtract the CS451 level measurement from the initial elevation measurement.
CS451/CS456 Submersible Water-Level Recording Sensor 14

For example, if the correct elevation of the water, as measured by a staff gage or other
measurement device, is 20 feet, and the CS451 provides a reading of 5.76 psig, then:
5.76 psig • 2.31 ft/psig = 13.3056 ft.
So, the offset is the following:
20 ft – 13.3056 ft = 6.6944 ft
Include an expression in the CRBasic program to account for this offset.
7.5 Changing nose cones
The procedure to change or replace a nose cone follows:
1. Remove the two screws (FIGURE 7-4 (p. 15)).
2. Pull the nose cone away from the sensor housing.
3. Insert the new nose cone into the sensor housing.
4. Replace and tighten the screws.
FIGURE 7-4. Screws on the standard nose cone (top), NPT nose cone (middle), and
weighted nose cone (bottom)
CS451/CS456 Submersible Water-Level Recording Sensor 15

8. Operation
8.1 Configuration 16
8.2 SDI-12 commands 19
8.3 Measuring multiple SDI-12 sensors 22
8.4 Unit command 22
8.5 Sample number command 23
8.1 Configuration
Table 8-1 (p. 16) shows default settings of the CS451/CS456.
Table 8-1: Factory settings
SDI-12 address 0
RS-232 baud rate 9600
Pressure/level units psig
Temperature units Celsius
Communicating with the CS451/CS456 requires the sensor to be either connected to a computer
or to an SDI-12 recorder. The sensor typically connects to a computer via the A200 sensor to
computer interface. Many SDI-12 recorders allow communication to the sensor via a terminal
screen. Configurable settings can be changed via SDI-12 commands or by using Campbell
Scientific software Device Configuration Utility. (Refer to the video SDI-12 Sensors | Transparent
Mode.)
8.1.1 Computer connection using the A200
The A200 or another device is required to connect the CS451/CS456 to a computer. This allows
sensor settings to be changed using the Device Configuration Utility.
8.1.1.1 Driver installation
If the A200 has not been previously plugged into your computer, the A200 driver needs to be
loaded onto your computer.
NOTE:
Drivers should be loaded before plugging the A200 into the computer.
CS451/CS456 Submersible Water-Level Recording Sensor 16

The A200 drivers can be downloaded, at no charge, from: www.campbellsci.com/downloads.
8.1.1.2 A200 wiring
One end of the A200 has a terminal block while the other end has a type B female USB port. The
terminal block provides 12V,G,Tx, and Rx terminals for connecting the sensor (see FIGURE 8-1 (p.
17) and Table 8-2 (p. 17)). The data cable shipped with the A200 has a USB type-A male
connector that attaches to a computer USB port, and a type B male connector that attaches to
the A200 USB port.
FIGURE 8-1. A200 Sensor-to-Computer Interface
Table 8-2: A200 wiring
Color Sensor cable label A200 terminal
Red 12V +12Vdc
Black G G
White C Tx
Blue G Rx
Yellow G G
Clear Signal ground G
8.1.1.3 Powering the sensor
The A200 provides power to the sensor when it is connected to a computer USB port. An internal
DC/DC converter boosts the 5 VDC supply from the USB connection to a 12 VDC output is
required to power the sensor.
CS451/CS456 Submersible Water-Level Recording Sensor 17