Campbell CS241 User manual

Revision: 05/2021
Copyright © 2020 – 2021
Campbell Scientific, Inc.

Table of contents
1. Introduction 1
2. Precautions 1
3. Initial inspection 1
4. QuickStart 2
5. Overview 4
6. Specifications 6
7. Installation 7
7.1 Circuit diagrams 8
7.2 Wiring 9
7.3 Data logger programming 11
7.3.1 Resistance measurement and conversion to temperature 12
7.4 Placement on a photovoltaic (PV) module 13
7.5 Mounting/cable strain relief 13
7.5.1 Adhesive mounting strip 13
7.5.2 Cable strain relief 13
7.5.3 Extreme sealing tape 15
7.6 Cable resistance/long cable lengths 16
7.7 Electrical noisy environments 17
8. Maintenance and troubleshooting 18
8.1 Maintenance 18
8.2 Troubleshooting 18
Appendix A. Importing Short Cut code into CRBasic Editor 19
Appendix B. Sensor material properties 20
B.1 3M F9473PC adhesive 20
Table of Contents - i

1. Introduction
The CS241 temperature sensor uses a precision 1000 ohm Class A platinum resistance
thermometer (PRT) to measure temperature. It is designed for measuring the back-of-
photovoltaic (PV) module temperature but also can be used to measure the surface temperature
of other devices. The CS241 can be measured with a 2-wire or 4-wire configuration and is
compatible with most Campbell Scientific data loggers.
NOTE:
This manual provides information only for CRBasic data loggers. The sensor is also
compatible with our retired Edlog data loggers. For Edlog data logger support, contact
Campbell Scientific. Support for Edlog data loggers is no longer free; see
www.campbellsci.com/news-edlog-retiring for more information.
2. Precautions
lREAD AND UNDERSTAND the Safety section at the back of this manual.
lDo not use epoxy to secure the sensor head to a PV module.
lBefore mounting, the installers need to wash their hands and then clean the back of the PV
module or other device using the isopropyl alcohol pad shipped with the sensor.
lPrying the sensor head off will likely damage both the sensor and PV module.
lProper strain relief of the cable is required after mounting the sensor to the measurement
surface (Mounting/cable strain relief (p. 13)).
lPlacement of the cable inside a rugged conduit is advisable for cable runs over 4.5 m (15 ft),
especially in locations subject to digging, mowing, traffic, power tools, animals, or lightning
strikes.
3. Initial inspection
lUpon receipt of the sensor, inspect the packaging and contents for damage. File damage
claims with the shipping company.
CS241 PT-1000 Class A, Back-of-Module Temperature Sensor1

lThe model number, cable length, and cable resistance are printed on a label at the
connection end of the cable. Check this information against the shipping documents to
ensure the expected product and cable length were received.
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
wiring terminals. Short Cut is available as a download on www.campbellsci.com . It is included
in installations of LoggerNet, RTDAQ, or PC400.
The following procedure also shows using Short Cut to program the CS241.
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 CS241. You can also locate the sensor in the
Sensors > Temperature folder. Double click the sensor model. The surface temperature
defaults to degree C. This can be changed by clicking the Temperature box and selecting
one of the other options. If using the 2-wire configuration, type the Cable Resistance. This
value is unique for each sensor, and is printed on the heat shrink label attached to the
sensor cable.
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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.
5. Repeat steps three and four for other sensors you want to measure. Click Next.
6. In Output Setup, type the scan rate, a meaningful table name, and the Data Output Storage
Interval.
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7. Select the measurement and its associated output option.
8. Click Finish and save the program. Send the program just created to the data logger if the
data logger is connected to the computer.
9. 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, or PC400 to make sure it is
making reasonable measurements.
5. Overview
The CS241 is a surface mountable platinum resistive thermometer (PRT) that measures back-of-
module temperature for solar energy applications. It uses a precision PT-1000 Class A PRT to
provide the highest level of accuracy. To withstand the harsh treatment that commonly occurs
with meteorological station installation, the sensing element is safely housed inside a specially
designed self-adhesive aluminum disk (FIGURE 5-1 (p. 5)).
The disk protects the PRT, particularly during installation, and promotes heat transfer from the
surface. An adhesive tab on the disk fastens the sensor to the measurement surface.
The CS241 provides PV stakeholders with highly accurate back-of-module temperature, even at
long cable lengths, in power performance modeling and simulation of solar energy applications.
Back-of-module temperature is critical for any evaluation of effective irradiance and power
conversion.
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FIGURE 5-1. CS241 temperature sensor
Benefits and features:
lDesigned for optimal performance on bifacial PV module
lEasy installation with maximum sensor-to-module bonding strength and smaller profile
lNIST-traceable, serialized calibration certificate supplied with every sensor
lMeets or exceeds IEC 61724 Class A performance specifications
lPrecision PT-1000 Class A sensing element
lCompliant with IEC 60751, DIN EN 60751 (according to IEC 751)
lSuitable for use on floating PV arrays
lSlim design to minimize sensor impact on bifaciality (<2% of full-size cell area)
lThermal conductance greater than 600 W/(m2 K)
lMaximum sensor-to-module bonding
lHigh temperature rating to 150 °C
lUser-selectable and standard cable lengths offered
l2-wire or 4-wire configurations to satisfy accuracy even at long cable lengths
lCompatible with Campbell Scientific CRBasic data loggers: CR6, CR3000, CR1000X, CR800
series, CR300 series, CR1000
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6. Specifications
Sensor: Precision 1000 ohm Class A platinum sensing element
Class A sensor accuracy: ± (0.15 + 0.002t) °C
Operating temperature range: –40 to 150 °C
Temperature coefficient: TCR = 3850 ppm/K
Long-term stability: Maximum R0 drift = 0.04% after 1000 hours at 400 °C
Measuring current: 0.1 to 0.3 mA
Temperature uncertainty: ±(0.3 to 0.4 °C) for the –40 to 100 °C measurement range
when using the CR1000X data logger
Disk diameter: 2.54 cm (1.0 in)
Height: 0.419 cm (0.165 in)
Disk material: Anodized aluminum
Weight: ~27 g (0.06 lb) with 1 m (3 ft) cable
Approvals: Conforms with the Restriction of Hazardous Substances
Directive (RoHS2)
Compliance: View compliance documents at:
www.campbellsci.com/cs241
 Meets or exceeds IEC 61724 Class A performance
specifications
Industrial standards: Compliant with IEC 60751, DIN EN 60751,
Industrial Design (IEC Class 4) (according to IEC 751)
IP rating: IP68 rating (self certified): 1 m (3 ft) submersion for 90
minutes
EMC compliance: Conforms with Electromagnetic Compatibility Directive
(EMC)
RoHS2: Conforms with Restriction of Hazardous Substances
Directive (RoHS2)
POE compliance: POE compliant (802.3af) to 100 meters when installed per
recommendations in TIA TSB-184
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CAT5e: Cable will meet CAT5e channel requirements to 100 meter
length
Sensor cable (sensor head-to-M12 connector)
Cable diameter: 0.216 cm (0.085 in)
Cable length: 0.9 m (3 ft)
Jacket material: White semi-gloss perfluoroalkoxy (PFA), insulated
Jacket rating: –75 to 250 °C
Minimum bend radius: 6 mm (0.25 in) at least 6 mm (0.25 in) away
from sensor disk
Connector: Circular plastic M12 , male 8-pin connector
Main cable (M12 connector to pigtail)
Cable diameter: 0.622 cm (0.245 in)
Jacket material: Black semi-gloss polyvinyl chloride (PVC), UL VW-1
sunlight resistant for outdoor use
UL: AWM 10012 1000V 105 °C
7. Installation
If you are programming your data logger with Short Cut, skip Wiring (p. 9) and Data logger
programming (p. 11). Short Cut does this work for you. See QuickStart (p. 2) for a Short Cut
tutorial. This section discusses the following:
7.1 Circuit diagrams 8
7.2 Wiring 9
7.3 Data logger programming 11
7.4 Placement on a photovoltaic (PV) module 13
7.5 Mounting/cable strain relief 13
7.6 Cable resistance/long cable lengths 16
7.7 Electrical noisy environments 17
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7.1 Circuit diagrams
FIGURE 7-1 (p. 8) provides the circuit diagram for the 2-wire configuration. FIGURE 7-2 (p. 8)
provides the circuit diagram for the 4-wire configuration.
FIGURE 7-1. 2-Wire Circuit Diagram
FIGURE 7-2. 4-Wire Circuit Diagram
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