Campbell 109 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 Air temperature installation 7
7.4 Water temperature installation 9
7.5 Soil temperature installation 9
8. Operation 10
8.1 Sensor schematic 10
8.2 Measurement and output linearization 10
8.3 Electrically noisy environments 11
8.4 Long cable lengths 11
9. Troubleshooting and maintenance 12
9.1 Troubleshooting 12
9.2 Maintenance 12
9.3 Calibration 13
10. Attributions and references 13
Appendix A. Importing Short Cut code into CRBasic Editor 14
Appendix B. Example program 15
Appendix C. Thermistor resistance and temperature 16
Table of Contents - i

1. Introduction
The 109 Temperature Probe uses a thermistor to measure temperature in air, 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 109 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
109 Temperature Probe1

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.
109 Temperature Probe2

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.
109 Temperature Probe3

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 109 is a rugged probe that accurately measures air, soil, or water temperature in a variety of
applications. The sensor consists of a thermistor encapsulated in an epoxy-filled aluminum
housing. This design allows the probe to be buried or submerged in water to 15m (50ft) or
21psi. When measuring air temperature, a six-plate radiation shield is normally used to mount
the 109 and limit solar radiation loading.
Features:
lMeasures air, soil, or water temperature
lCompatible with AM16/32-series multiplexers
lEasy to install or remove
lDurable
109 Temperature Probe4

lCompatible CRBasic data loggers: CR6, CR3000, CR1000X, CR800-series, CR300-series,
CR1000
6. Specifications
Sensor element: Measurement Specialties 100K3A1iA thermistor
Survival range: –50 to 100 °C
Measurement range: –50 to 70 °C
Time constant in air: 30 to 60 s in a wind speed of 5 m/s
Maximum cable length: 305 m (1000 ft)
Accuracy1
Worst case: ±0.60 °C (–50 to 70 °C)
±0.25 °C (–10 to 70 °C)
Interchangeability error: ±0.10 °C (0 to 70 °C)
±0.13 °C at –10 °C
±0.15 °C at –20 °C
±0.18 °C at –30 °C
±0.20 °C at –40 °C
±0.50 °C at –50 °C
Steinhart-Hart equation error: ≤ 0.03 °C (–50 to 70 °C)
Probe weight and dimensions 
Weight with 10 ft cable: 136 g (5 oz)
Length: 10.4 cm (4.1 in)
Diameter: 0.762 cm (0.3 in)
Compliance: View the EU Declaration of Conformity at
www.campbellsci.com/109
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.
109 Temperature Probe5

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
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. 14). Programming basics are provided in the following
section. A complete program example can be found in Example program (p. 15).
109 Temperature Probe6

If the 109 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. 11) and Long cable lengths (p. 11).
Details of 109 probe measurement and linearization of the thermistor output are provided in
Measurement and output linearization (p. 10).
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. 10) 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. 11))
lCompensate for long cable lengths — Set SettlingTime to 20000 (see Long cable
lengths (p. 11))
7.3 Air temperature installation
For air temperature measurements, locate probes over an open, level area at least 9 m (EPA;
Attributions and references (p. 13)) in diameter. The surface should be covered by short grass or
the natural earth surface where grass does not grow. Probes should be located at a distance of at
least four times the height of any nearby obstruction, and at least 30m (EPA) from large paved
areas. Sensors should be protected from thermal radiation, and adequately ventilated.
Standard air temperature measurement heights:
l1.25 to 2.0 m (WMO; Attributions and references (p. 13))
l2.0 m (EPA; Attributions and references (p. 13))
l2.0 m and 10.0 m for temperature difference (EPA)
109 Temperature Probe7

When exposed to sunlight, the 109 should be housed in a six-plate solar radiation shield. Six-
plate shields offered by Campbell Scientific are models 41303-5A, 41303-5B, or RAD06.
The white color of these shields reflects solar radiation, and the louvered construction allows air
to pass freely through, thereby keeping the probe at or near ambient temperature. The RAD06
uses a double-louvered design that offers improved sensor protection from insect intrusion and
driving rain and snow. In addition, the RAD06 shield has lower self-heating in bright sunlight
combined with higher temperatures (> 24 °C (75 °F)) and low wind speeds (< 2 m/s (4.5 mph)),
giving a better measurement.
The 41303-5A and RAD06 attach to a crossarm, mast, or user-supplied pipe with a 2.5 to 5.3cm
(1.0 to 2.1in) outer diameter. The 41303-5B attaches to a CM500-series pole or a user-supplied
pole with a 5.1cm (2.4in) outer diameter.
Tools required for installing a radiation shield to a tripod or tower include:
l1/2-inch open end wrench
lUV resistant cable ties
ladjustable wrench with a minimum 1-1/2 inch jaw size
FIGURE 7-1. Installing a 109 and 41303-5A Radiation Shield on a CM200-Series Crossarm
109 Temperature Probe8