Campbell CS547A User manual

Revision: 02/2022
Copyright © 1994– 2022
Campbell Scientific, Inc.

Table of contents
1. Introduction 1
2. Precautions 1
3. Initial inspection 1
4. QuickStart 1
5. Overview 4
5.1 EC sensor 5
5.2 Conductivity interface 5
6. Specifications 6
6.1 CS574A probe 6
6.2 Temperature sensor 7
6.3 A547 interface 7
7. Installation 8
7.1 Site selection 8
7.2 Mounting 8
7.3 Wiring 8
7.4 Programming 9
7.4.1 EC measurement 10
7.4.2 Ionization correction 10
7.4.3 Temperature measurement 10
7.4.4 Correct EC measurement for temperature errors 11
7.4.5 Output processing 11
8. Operation 12
8.1 Calibration 12
8.1.1 Conversion factors 12
8.1.2 Typical ranges 12
8.1.3 Factory calibration 12
8.1.4 Field calibration 12
8.2 Deriving a temperature compensation coefficient 13
8.3 Analysis of ionization-error correction 13
Table of Contents - i

8.4 Schematics 14
9. Maintenance 15
Appendix A. Importing Short Cut code into CRBasic Editor 16
Table of Contents - ii

1. Introduction
The CS574A probe monitors the electrical conductivity (EC) and temperature of fresh water. It
connects to a Campbell Scientific data logger using the A547 interface. This probe is compatible
with most Campbell Scientific data loggers.
NOTE:
This manual provides information only for CRBasic data loggers. For retired Edlog data logger
support, see an older manual at www.campbellsci.com/old-manuals .
2. Precautions
lREAD AND UNDERSTAND the Safety section at the back of this manual.
lThe CS574A and A547 are precision instruments. Please handle them with care.
lCAUTION: Rapid heating and cooling of the CS574A, such as leaving it in the sun and then
submersing it in a cold stream, may cause irreparable damage.
lDo not use the CS574A with long cable lengths in an electrically noisy environment.
3. Initial inspection
lUpon receipt of the CS574A and A547, inspect the packaging and contents for damage.
File damage claims with the shipping company.
lImmediately check package contents against the shipping documentation. Contact
Campbell Scientific about any discrepancies.
4. QuickStart
A video that describes data logger programming using Short Cut is available at:
www.campbellsci.com/videos/cr1000x-data logger-getting-started-program-part-3 .Short
Cut is an easy way to program your data logger to measure the sensor and assign data logger
CS574A Conductivity and Temperature Probe and A547 Interface 1

wiring terminals. Short Cut is available as a download on www.campbellsci.com . It is included
in installations of LoggerNet,RTDAQ, and PC400.
The following procedure also shows using Short Cut to program the CS574A.
1. Open Short Cut and click Create New Program.
2. Double-click the data logger model.
3. In the Available Sensors and Devices box, type CS574A or locate the sensor in the Sensors
>Water >Quality >CS547A Conductivity and Temperature Probe folder. Double click on
the CS547A Conductivity and Temperature Probe. Type the Cell Constant Kc (printed on
the sensor label), Lead Length in Feet, and Temperature Correction (Deriving a
temperature compensation coefficient (p. 13)). Temperature defaults to degree Celsius. This
can be changed by clicking the Deg C box and selecting Deg F, for degrees Fahrenheit, or K
for Kelvin.
CS574A Conductivity and Temperature Probe and A547 Interface 2

4. Click on the Wiring tab to see how the sensor is to be wired to the A547 and data logger.
5. In Output Setup, type the scan rate, meaningful table names, and Data Output Storage
Interval. Click Next.
CS574A Conductivity and Temperature Probe and A547 Interface 3

6. Select the measurement and its associated output option.
7. Click Finish and save the program. Send the program to the data logger if the data logger
is connected to the computer.
8. If the sensor is connected to the data logger, check the output of the sensor in the data
display in LoggerNet,RTDAQ, or PC400 to make sure it is making reasonable
measurements.
5. Overview
One A547 interface is required for each CS574A when used directly with the data logger; multiple
CS574A probes can connect to one AM16/32B multiplexer and one A547 interface.
Electrical conductivity (EC) of a solution is a simple physical property, but measurements can be
difficult to interpret. This manual instructs the user how to make EC measurements with the
CS574A. Accuracy specifications apply to measurements of EC in water containing KCl, Na2SO4,
NaHCO3, and/or NaCl, which are typical calibration compounds, and to EC not yet compensated
for temperature effects.
Statements made on methods of temperature compensation or estimating dissolved solids are
included to introduce common ways of refining and interpreting data, but are not definitive.
Authoritative sources to consult include the USGS Water-Supply Paper 1473, The pH and
Conductivity Handbook published by OMEGA Engineering, physical chemistry texts, and other
sources.
CS574A Conductivity and Temperature Probe and A547 Interface 4

Features:
lCompatible with AM16/32-series multiplexers allowing measurement of multiple sensors
lRounded ends facilitate installation and removal
lEasy to clean
lCorrosion resistant
lWeighted option available for stand-alone submersion
lCompatible with Campbell Scientific CRBasic data loggers: CR6, CR1000X, CR800-series,
CR3000, CR1000
5.1 EC sensor
The CS574A consists of three stainless steel rings mounted in an epoxy tube (FIGURE 5-1 (p. 5)).
Resistance of water in the tube is measured by excitation of the center electrode with positive
and negative voltage. This electrode configuration eliminates the ground looping problems
associated with sensors in electrical contact with earth ground. Temperature is measured with a
thermistor in a three-wire half-bridge configuration.
FIGURE 5-1. CS574A Conductivity and Temperature Probe
5.2 Conductivity interface
The A547 interface (FIGURE 5-2 (p. 6)) consists of blocking capacitors and bridge completion
resistors housed in a metal case. Screw terminals are provided for connecting the data logger,
and a water conductivity probe or multiplexer. Keep the interface in a non-condensing
environment that is maintained within the temperature range of the unit. Typically, the A547 is
housed in the data logger enclosure.
CS574A Conductivity and Temperature Probe and A547 Interface 5

FIGURE 5-2. A547 Interface
6. Specifications
6.1 CS574A probe
Housing: Epoxy
Length: 89 mm (3.5 in)
Width: 25.4 mm (1 in)
Height: 19 mm (0.75 in)
Minimum pipe ID in which
CS574A fits: 28 mm (1.1 in)
Maximum cable length: 305 m (1000 ft). The sensor must be ordered with desired
length as cable cannot be added to existing probes.
Depth rating: 305 m (1000 ft) maximum
pH range: Solution pH of less than 3.0 or greater than 9.0 may damage
the stainless steel housing.
Electrodes: Passivated 316 SS with DC isolation capacitors.
Cell constant: Individually calibrated. The cell constant (Kc) is found on a
label near the termination of the cable.
Operating temperature range: 0 to 50 °C
CS574A Conductivity and Temperature Probe and A547 Interface 6

EC range: ~ 0.005 to 7.0 mS/cm
EC measurement error
Bridge measurement error: <1%
Calibration error: In KCl and Na2SO4, NaHCO3, and NaCl standard solutions
at 25 °C:
±5% of reading (0.44 to 7.0 mS/cm)
±10% of reading (0.005 to 0.44 mS/cm)
Ionization error of KCl and Na+
solutions after correction: < 2.0%, 0.45 to 7.0 mS/cm
< 8.0%, 0.005 to 0.45 mS/cm
Weight with 4 ft cable: 120 g (4.2 oz)
6.2 Temperature sensor
Thermistor: Betatherm 100K6A1
Range: 0 to 50 °C
Accuracy1
Worst case: ±0.4 °C ( –24 to 48 °C)
±0.9 °C ( –35 to 50 °C)
Interchangeability error: ±0.10 °C (0 to 50 °C)
±0.20 °C at –10 °C
±0.30 °C at –20 °C
±0.40 °C at –30 °C
±0.50 °C at –40 °C
Steinhart-Hart equation error: ≤±0.01 °C ( –35 to 50 °C)
1Overall probe accuracy is a combination of thermistor interchangeability, bridge-resistor accuracy, and error of the
Steinhart-Hart equation. Bridge resistors have 0.1% tolerance with a 10 ppm temperature coefficient.
Interchangeability is the principle component error.
6.3 A547 interface
Length: 64 mm (2.5 in)
Height: 46 mm (1.8 in)
Width: 23 mm (0.9 in)
CS574A Conductivity and Temperature Probe and A547 Interface 7