Campbell CS240 User manual

Revision: 08/2020
Copyright © 2017 – 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 6
7. Installation 8
7.1 Placement on a photovoltaic (PV) module 8
7.2 Mounting/cable strain relief 8
7.2.1 Adhesive mounting strip 9
7.2.2 Extreme sealing tape 9
7.2.3 Strain relief of CS240DM analog-to-digital module 11
7.3 Wiring 11
7.3.1 CS240-to-data-logger wiring 12
7.3.2 CS240DM wiring 13
7.4 Data logger programming 14
7.4.1 CS240 programming 14
7.4.1.1 Resistance measurement 14
7.4.1.2 Converting resistance measurement to temperature 15
7.4.2 CS240DM programming 15
8. Operation 16
8.1 Electrical noisy environments 16
8.2 Long cable lengths 16
8.2.1 CS240 cable resistance/long cable lengths 16
8.2.2 CS240DM long cable lengths 17
8.3 Modbus register map 18
8.4 CS240DM and Device Configuration Utility 19
9. Maintenance and troubleshooting 21
9.1 Maintenance 21
Table of Contents - i

9.2 Troubleshooting 21
Appendix A. Importing Short Cut code into CRBasic Editor 22
Appendix B. Example programs 23
B.1 CS240 two-wire configuration programs 24
B.2 CS240 four-wire configuration programs 28
B.3 CS240DM program 31
Appendix C. Sensor material properties 33
C.1 3M F9473PC adhesive 33
Table of Contents - ii

1. Introduction
The CS240 and CS240DM temperature sensors use a precision 1000 ohm class A platinum
resistance thermometer (PRT) to measure temperature. They are designed for measuring the
back-of-photovoltaic (PV) module temperature but also can be used to measure the surface
temperature of other devices. The CS240 can be measured with a 2-wire or 4-wire configuration
and is compatible with most Campbell Scientific data loggers. The CS240DM has a digital RS-485
output that can be directly read by a MeteoPV, CR6, CR1000X, or Modbus RTU RS-485 network.
Other Campbell Scientific data loggers can use an MD485 multidrop interface to read the
CS240DM output.
NOTE:
This manual provides information only for CRBasic data loggers. The CS240 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 with ethyl alcohol.
lDo not place tape over the sensor molding; only place tape on the metal disk portion of
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. 8)).
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.
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 1

3. Initial inspection
lUpon receipt of the sensor, inspect the packaging and contents for damage. File damage
claims with the shipping company.
lThe model number, cable length, and cable resistance (CS240 only) 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
The information provided in this section is for the CS240.
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, PC400, or PC200W.
The following procedure also shows using Short Cut to program the CS240 and CS240DM.
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 CS240. 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 CS240 and CS240DM, and is printed on the heat shrink label
attached to the sensor cable.
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 2

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.
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 3

6. In Output Setup, type the scan rate, a meaningful table name, and the Data Output
Storage Interval.
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, PC400, or PC200W to make
sure it is making reasonable measurements.
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 4

5. Overview
The CS240 and CS240DM are surface mountable platinum resistive thermometers (PRT) that
measure back-of-module temperature for solar energy applications. They use a precision PT-1000
class A PRT to provide the highest level of accuracy. To withstand the harsh treatment commonly
seen in 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. If the
temperature may exceed 70 °C, extreme sealing tape is also required to secure the sensor.
The CS240DM includes a Campbell Scientific precision analog-to-digital, smart-sensor module
for making the measurements. The module design is optimized for the class A PRT that
minimizes self-heating and lead-wire resistance. Measurement electronics are surge protected
with 1200 V isolation and environmentally protected with a rugged overmolding with an IP65
rating.
The CS240 and CS240DM provide 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.
FIGURE 5-1. CS240/CS240DM temperature sensor
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 5

Features:
lPrecision PT-1000 class A sensing element
lUser-selectable and standard cable lengths offered
lRugged design holds up in harsh conditions and conduit installations
lSelf-adhesive backing for easy mounting lasts decades
lCS240 has 2-wire or 4-wire configurations to satisfy accuracy even at long cable lengths
lCS240 compatible with Campbell Scientific CRBasic data loggers: CR6, CR3000, CR1000X,
CR800 series, CR300 series, CR1000, and CR5000
lCS240DM compatible with Campbell Scientific CRBasic data loggers: CR6, CR1000X,
CR3000 (with MD485), CR800 series (with MD485), CR300 series (with MD485), CR1000
(with MD485),
lCS240DM easily interfaces with the MeteoPV Platform without coding
lCS240DM can connect directly with Modbus RTU RS-485 Networks
lCalibration services with certification available
6. Specifications
Sensor: Precision 1000 ohm class A platinum sensing element
Class A sensor accuracy: ± (0.15 + 0.002t) °C
Temperature range: –40 to 135 °C
Temperature coefficient: TCR = 3850 ppm/K
Long-term stability: Max Ro drift = 0.04% after 1000 hours at 400 °C
CS240 measuring current: 0.1 to 0.3 mA
Disk diameter: 2.54 cm (1.0 in)
Overall sensor length: 6.35 cm (2.5 in)
Overmolded joint dimensions
Width: 1.12 cm (0.44 in)
Height: 1.47 cm (0.58 in)
Length: 5.72 cm (2.25 in)
Cable diameter: 0.622 cm (0.245 in)
Cable temperature rating: 105°C
Disk material: Anodized aluminum
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 6

Weight: 90.7 g (0.2 lb) with 3.2 m (10.5 ft) cable
CS240DManalog-to-digitalmodule: 24-bit ADC
A/D measurement uncertainty: ±0.015 °C
Supply voltage: 5 to 30 VDC
Power consumption: 15 mA
Surge protection: 1200 V isolation
Environmental protection: Rugged overmolding with IP65 rating
Approvals: UL AWM 2586 1000V 105 °C; CSA AWM 600V 105 °C FT1
Conforms with Electromagnetic Compatibility Directive
(EMC)
Conforms with the Restriction of Hazardous Substances
Directive (RoHS2)
Compliance: View compliance documents at:
www.campbellsci.com/cs240 or
www.campbellsci.com/cs240dm
Compliant with IEC 60751, DIN EN 60751,
Industrial Design (IEC Class 4) (according to IEC 751)
CS240 cable
Jacket material: Black semi-gloss PVC, UL VW-1 sunlight resistant for
outdoor use
Wire size and type: 24 AWG (7/32) tinned copper
Nominal wire diameter: 0.61 mm (0.024 in)
Insulation type: PVC
UL: AWM 10012 1000V 105 °C
Filler: Fibrillated polypropylene as required for uniform
round construction.
Drain: 24 AWG (7/32) tinned copper (cabled, touching foil)
Shield: Aluminum/mylar (100% coverage, 25% minimum overlap,
foil facing in)
CS240 and CS240DM PT-1000 Class A, Back-of-Module Temperature Sensors 7