Campbell TEMPERATURE PROBE 109SS User manual

Revision: 05/2021
Copyright © 1983 – 2021
Campbell Scientific, Inc.

Table of contents
1. Introduction 1
2. Precautions 1
3. Initial inspection 1
4. QuickStart 1
5. Overview 4
6. Specifications 5
7. Installation 6
7.1 Wiring to data logger 6
7.2 Data logger programming 6
7.2.1 Therm109() instruction 7
7.3 Water temperature installation 7
7.4 Soil temperature installation 8
8. Operation 8
8.1 Sensor schematic 8
8.2 Measurement and output linearization 8
8.3 Electrically noisy environments 9
8.4 Long cable lengths 9
9. Troubleshooting and maintenance 10
9.1 Troubleshooting 10
9.2 Maintenance 11
9.3 Calibration 11
10. Attributions and references 11
Appendix A. Importing Short Cut code into CRBasic Editor 12
Appendix B. Example program 13
Appendix C. Thermistor resistance and temperature 14
Table of Contents - i

1. Introduction
The 109SS Temperature Probe uses a thermistor to measure temperature in soil and water. It
easily interfaces with most Campbell Scientific data loggers and can be used in a variety of
applications.
For Edlog data logger support, check the availability of an older manual at
www.campbellsci.com/old-manuals , or contact Campbell Scientific for assistance.
2. Precautions
READ AND UNDERSTAND the Safety section at the back of this manual.
Santoprene® rubber, which composes the black outer jacket of the 109SS cable, will support
combustion in air. It is used because of its resistance to temperature extremes, moisture, and UV
degradation. It is rated as slow burning when tested according to U.L. 94 H.B. and passes
FMVSS302. However, local fire codes may preclude its use inside buildings.
3. Initial inspection
Check the packaging and contents of the shipment. If damage occurred during transport,
immediately file a claim with the carrier. Contact Campbell Scientific to facilitate repair or
replacement.
Check model information against the shipping documents to ensure the expected products and
the correct lengths of cable are received. Model numbers are found on each product. On cables
and cabled items, the model number is usually found at the connection end of the cable. Report
any shortages immediately to Campbell Scientific.
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
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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, and PC400.
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.
3. In the Available Sensors and Devices box, type 109 or find the 109 in the Sensors >
Temperature folder. Double-click the 109 Temperature Probe. Data 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.
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4. Click 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 being measured. Click Next.
6. In Output Setup, type the scan rate, Data Output Storage Intervals, and meaningful table
names.
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7. Select the measurement and its associated output option.
8. Click Finish and save the program. Send the program 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
display in LoggerNet, RTDAQ, or PC400 to make sure it is making reasonable
measurements.
5. Overview
The 109SS is a rugged probe that accurately measures soil or water temperature in a variety of
applications. The sensor consists of a thermistor encased in a stainless-steel sheath. This design
protects the thermistor, allowing the 109SS to be buried or submerged in harsh, corrosive
environments. It can be submerged in water to 45m (150ft) or 63psi.
Features:
lMeasures soil or water temperature
lCompatible with AM16/32-series multiplexers
lEasy to install or remove
lDurable
lCompatible CRBasic data loggers: CR6, CR3000, CR1000X, CR800-series, CR300-series,
CR1000
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6. Specifications
Sensor element: Measurement Specialties Micro-BetaCHIP 10K3MCD1
thermistor
Survival range 
Thermistor: –50 to 100 °C
Overmolded joint and cable: –50 to 70 °C
Measurement range: –40 to 70 °C
Time constant: 31 s in still air
7.5 s in a wind speed of 3 m/s
0.5 s in rolling water or antifreeze
Maximum cable length: 305 m (1000 ft)
Accuracy1
Worst case: ±0.60 °C (–40 to 70 °C)
±0.49 °C (–20 to 70 °C)
Maximum submergence: 45 m (150 ft) (63 psi)
Interchangeability error: ±0.60 °C at –40 °C
±0.38 °C at 0 °C
±0.10 °C at 25 °C
±0.30 °C at 50 °C
±0.45 °C at 70 °C
Steinhart-Hart equation error: ≤ 0.02 °C (–40 to 70 °C)
Stainless-steel sheath 
Diameter: 0.16 cm (0.063 in)
Length: 5.84 cm (2.3 in)
Overmolded joint 
Diameter: 1.02 cm (0.40 in)
Length: 4.24 cm (1.67 in)
Cable: Santoprene®, 0.220 in diameter
Cable/probe connection: ATUMTM heat shrink
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Macromelt® overmolded joint
Weight: 0.2 lb per 10.5 ft cable
Compliance: View the EU Declaration of Conformity at
www.campbellsci.com/109ss
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. If needed, an estimate of the interchangeability error for 0 to
50°C, that can be used as the Offset parameter of the Therm109() instruction, can be determined with a 1-point
or 2-point calibration.
7. Installation
If you are programming your data logger with Short Cut, skip Wiring to data logger (p. 6) and
Data logger programming (p. 6). Short Cut does this work for you. See QuickStart (p. 1) for a Short
Cut tutorial.
7.1 Wiring to data logger
Table 7-1: Wire color, function, and data logger connection
Wire color Wire function Data logger connection terminal
Black Voltage-excitationinput U configured for voltage excitation1,
EX, VX (voltage excitation)
Red Analog-voltageoutput U configured for single-ended analog input1,
SE (single-ended, analog-voltage input)
Purple Bridge-resistor ⏚ (analog ground)
Clear EMF shield ⏚ (analog ground)
1U terminals are automatically configured by the measurement instruction.
7.2 Data logger programming
Short Cut is the best source for up-to-date data logger programming code.
If your data acquisition requirements are simple, you can probably create and maintain a data
logger program exclusively with Short Cut. If your data acquisition needs are more complex, the
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files 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. 1). If you wish 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. 12). Programming basics are provided in the following
section. A complete program example can be found in Example program (p. 13).
If the 109SS probe is to be used with long cable lengths or in electrically noisy environments,
consider employing the measurement programming techniques outlined in Electrically noisy
environments (p. 9) and Long cable lengths (p. 9).
Details of 109SS probe measurement and linearization of the thermistor output are provided in
Measurement and output linearization (p. 8).
7.2.1 Therm109() instruction
The Therm109() measurement instruction programs CRBasic data loggers to measure this
sensor. It applies a precise excitation voltage, makes a half-bridge resistance measurement, and
converts the result to temperature using the Steinhart-Hart equation. See Measurement and
output linearization (p. 8) for more information. Therm109() instruction and parameters are as
follows:
Therm109(Dest, Reps, SEChan, VxChan, SettlingTime, Integ/fN1, Mult, Offset)

Variations:
lTemperature reported as °C — set Mult to 1 and Offset to 0
lTemperature reported as °F — set Mult to 1.8 and Offset to 32
lAC mains noise filtering — set Integ/fN1 to the 60 Hz or 50 Hz option (see Electrically
noisy environments (p. 9))
lCompensate for long cable lengths — Set SettlingTime to 20000 (see Long cable
lengths (p. 9))
7.3 Water temperature installation
109SS probes can be submerged to 15m (50ft) or 21psi. The 109SS is not weighted, so a
weighting system should be added, or the probe secured to a submerged object such as a piling.
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7.4 Soil temperature installation
The 109SS tends to measure the average temperature over its length, so burying the probe such
that the measurement tip is horizontal to the soil surface at the desired depth is usually preferred.
The maximum burial depth for soil that could become saturated with water is dictated by the
maximum water pressure allowed for the sensor, which is 21psi.
One or two coils of cable should also be buried in a shallow installation. Burial of some cable
mitigates the effect of solar heating of the above ground cable on the temperature
measurement.
Placement of the cable inside a rugged conduit may be necessary for long cable runs, especially
in locations subject to digging, mowing, traffic, use of power tools, or lightning strikes.
8. Operation
8.1 Sensor schematic
FIGURE 8-1. 109SS thermistor probe schematic
8.2 Measurement and output linearization
CRBasic instruction Therm109() measures the 109SS probe thermistor and automatically
converts the result to temperature. With reference to the previous FIGURE 8-1 (p. 8), Therm109()
applies 2500mV excitation at the Vx line and measures the voltage drop across the 24.9kΩ
resistor at the Vs line.
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