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


FIGURE 7-2. 109 and 41303-5A Radiation Shield on a tripod mast (left).
109 and RAD06 Radiation Shield on a CM200-Series Crossarm (right).
The 109 is held in the 41303-5A radiation shield by a mounting clamp at the bottom (FIGURE 7-1
(p. 8) and FIGURE 7-2 (p. 9) left). Loosen the mounting clamp screws, and insert the probe
through the clamp. Tighten the screws to secure the sensor, and route the sensor cable to the
instrument enclosure.
The 109 is held in the RAD06 radiation shield by inserting the sensor through the sensor gland at
the bottom of the shield (FIGURE 7-2 (p. 9) right). Loosen the nut on the gland, and insert the
probe into the shield. Tighten the nut on the sensor gland using an adjustable wrench until the
sensor is securely held in place. Route the sensor cable to the instrument enclosure.
Secure the cable to the tripod or tower using cable ties.
7.4 Water temperature installation
109 probes can be submerged to 15m (50ft) or 21psi. The 109 is not weighted, so a weighting
system should be added, or the probe secured to a submerged object such as a piling.
7.5 Soil temperature installation
The 109 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.
109 Temperature Probe9

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. 109 thermistor probe schematic
8.2 Measurement and output linearization
CRBasic instruction Therm109() measures the 109 probe thermistor and automatically converts
the result to temperature. With reference to the previous FIGURE 8-1 (p. 10), Therm109() applies
2500mV excitation at the Vx line and measures the voltage drop across the 24.9kΩ resistor at
the Vs line.
The ratio of measured voltage (Vs) to excitation voltage (Vx) is related to thermistor resistance
(Rs) and the 24.9kΩ bridge resistor as described in the following equations:
Vs/Vx = 24900 Ω / (Rs + 24900 Ω)
Solving for Rs:
Rs + 24900 Ω = 24900 Ω • (Vx/Vs)
Rs = 24900 Ω • ((Vx/Vs) – 1)
The relationship of Rs to temperature is tabulated in Thermistor resistance and temperature (p.
16), but is calculated by Therm109() using the Steinhart-Hart equation, described as follows:
Tc = (1 / (A + B • ln (Rs) + C • (ln (Rs))3)) – 273.15
109 Temperature Probe10

where:
Tc = temperature in degrees Celsius (°C)
A1 = 1.129241E–3
B1 = 2.341077E–4
C1 = 8.775468E–8
1Coefficients provided by Measurement Specialties™.
8.3 Electrically noisy environments
EMF noise emanating from the ac mains power grid can be a significant source of measurement
error. 60Hz noise is common in the United States. 50Hz noise is common in Europe and other
regions. This noise can usually be filtered out.
The following code snip examples filter 60 Hz noise.
CR6-series data logger example:
Therm109(T109_C,1,U1,U10,20000,60,1.0,0.0)

CR800-series and CR3000 data loggers example:
Therm109(T109_C,1,1,1,20000,_60Hz,1.0,0.0)
8.4 Long cable lengths
Long cable lengths (>50 ft) may require longer than normal analog measurement settling times.
Enter a longer settling time in the SettlingTime parameter of the Therm109() instruction.
Campbell Scientific suggests doubling the settling time every 50ft. The following code snip
examples increase settling time by 20000µs by placing 20000 as the argument in the
SettlingTime parameter:
CR6-series data logger example:
Therm109(T109_C,1,U1,U10,20000,60,1.0,0.0)

CR800-series and CR3000 data loggers example:
Therm109(T109_C,1,1,1,20000,_60Hz,1.0,0.0)
109 Temperature Probe11

9. Troubleshooting and
maintenance
NOTE:
All factory repairs and recalibrations require a returned material authorization (RMA) and
completion of the “Declaration of Hazardous Material and Decontamination” form. Refer to
the Assistance page at the back of this manual for more information.
9.1 Troubleshooting
Symptom: Temperature is reported as NAN, –INF, or incorrect temperature.
Verify wires are connected to the terminals specified in the Therm109() instruction: red to
single-ended analog input (SE or U), black to switched excitation (VX/EX or U), and purple to
ground (⏚).
Symptom: Incorrect temperature is reported.
Verify the Mult and Offset arguments in Therm109() are correct for the desired units
(Data logger programming (p. 6)). Check the cable for signs of damage and possible moisture
intrusion.
Symptom: Unstable temperature is reported.
Probably a result of electromagnetic interference. Try using the 50 Hz or 60 Hz options for the
fN1 parameter, and/or increasing the settling time as described in Electrically noisy
environments (p. 11) and Long cable lengths (p. 11). Ensure the clear wire is connected to data
logger ground, and the data logger is properly grounded.
9.2 Maintenance
The 109 probe requires minimal maintenance. For air temperature measurements, check the
radiation shield monthly to make sure it is free from dust and debris. To clean the shield, first
remove the sensor. Dismount the shield. Brush all loose dirt off. If more effort is needed, use
warm, soapy water and a soft cloth or brush to thoroughly clean the shield. Allow the shield to
dry before remounting.
Periodically check cabling for signs of damage and possible moisture intrusion.
109 Temperature Probe12

9.3 Calibration
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. Calibration of the 109 probe is not necessary unless the accuracy needed in the
sensor data requires correction of the thermistor interchangeability offset described in
Specifications (p. 5).
10. Attributions and references
Santoprene® is a registered trademark of Exxon Mobile Corporation.
Measurement Specialties™ is a trademarked global designer and manufacturer of sensors and
sensor-based systems.
EPA installation standard: Quality Assurance Handbook for Air Pollution Measurement Systems –
Volume IV: Meteorological Measurements Version 2.0
WMO standard: WMO No. 8, Seventh edition, 6 Aug 2008 Guide to Meteorological Instruments
and Methods of Observation
109 Temperature Probe13

Appendix A. Importing Short
Cut code into CRBasic Editor
Short Cut creates a .DEF file that contains wiring information and a program file that can be
imported into the CRBasic Editor. By default, these files reside in the C:\campbellsci\SCWin folder.
Import Short Cut program file and wiring information into CRBasic Editor:
1. Create the Short Cut program. After saving the Short Cut program, click the Advanced tab
then the CRBasic Editor button. A program file with a generic name will open in CRBasic.
Provide a meaningful name and save the CRBasic program. This program can now be
edited for additional refinement.
NOTE:
Once the file is edited with CRBasic Editor, Short Cut can no longer be used to edit the
program it created.
2. To add the Short Cut wiring information into the new CRBasic program, open the .DEF file
located in the C:\campbellsci\SCWin folder, and copy the wiring information, which is at
the beginning of the .DEF file.
3. Go into the CRBasic program and paste the wiring information into it.
4. In the CRBasic program, highlight the wiring information, right-click, and select Comment
Block. This adds an apostrophe (') to the beginning of each of the highlighted lines, which
instructs the data logger compiler to ignore those lines when compiling. The Comment
Block feature is demonstrated at about 5:10 in the CRBasic | Features video .
109 Temperature Probe14

Appendix B. Example program
This following example measures one 109 temperature probe once a second and stores the
average temperature every 60 minutes.
CRBasic Example 1: CR1000X program that measures the 109
'Program measures one 109 temperature probe once a second and
'stores the average temperature every 60 minutes.

'Wiring Diagram
'==============
'Probe
'WireData logger
'ColorFunctionTerminal
'-------------------
'BlackVoltage-excitation inputVX1/EX1
'RedAnalog-voltage outputSE1
'PurpleBridge-resistor groundGround Symbol
'ClearShieldGround Symbol

'Declare the variables for the temperature measurement
Public T109_C

'Define a data table for 60 minute averages:
DataTable(Hourly,True,-1)
DataInterval(0,60,Min,0)
Average(1,T109_C,IEEE4,0)

EndTable

BeginProg
Scan(1,Sec,1,0)
'Measure the temperature
Therm109(T109_C,1,1,Vx1,0,60,1.0,0.0)
'Call Data Table
CallTable(Hourly)
NextScan
EndProg
109 Temperature Probe15

Appendix C. Thermistor
resistance and temperature

Table C-1: 109 thermistor resistance and temperature1
Actual temperature (°C) 10K3A1iA thermistor resistance (Ω) CRBasic Therm109() output (°C)
-40 336098 -40.00
-39 314553 -39.00
-38 294524 -38.00
-37 275897 -37.00
-36 258563 -36.00
-35 242427 -35.00
-34 227398 -34.00
-33 213394 -33.00
-32 200339 -32.00
-31 188163 -31.00
-30 176803 -30.00
-29 166198 -29.00
-28 156294 -28.00
-27 147042 -27.00
-26 138393 -26.00
-25 130306 -25.00
-24 122741 -24.00
-23 115661 -23.00
-22 109032 -22.00
-21 102824 -21.00
109 Temperature Probe16

Table C-1: 109 thermistor resistance and temperature1
Actual temperature (°C) 10K3A1iA thermistor resistance (Ω) CRBasic Therm109() output (°C)
-20 97006 -20.00
-19 91553 -19.00
-18 86439 -18.00
-17 81641 -17.00
-16 77138 -16.00
-15 72911 -15.00
-14 68940 -14.00
-13 65209 -13.00
-12 61703 -12.00
-11 58405 -11.00
-10 55304 -10.00
-9 52385 -9.00
-8 49638 -8.00
-7 47050 -7.00
-6 44613 -6.00
-5 42317 -5.00
-4 40151 -4.00
-3 38110 -3.00
-2 36184 -2.00
-1 34366 -1.00
0 32651 0.00
1 31031 1.00
2 29500 2.00
3 28054 3.00
4 26687 4.00
5 25395 5.00
109 Temperature Probe17

Table C-1: 109 thermistor resistance and temperature1
Actual temperature (°C) 10K3A1iA thermistor resistance (Ω) CRBasic Therm109() output (°C)
6 24172 6.00
7 23016 7.00
8 21921 8.00
9 20885 9.00
10 19903 10.00
11 18973 11.00
12 18092 12.00
13 17257 13.00
14 16465 14.00
15 15714 15.00
16 15001 16.00
17 14324 17.00
18 13682 18.00
19 13073 19.00
20 12493 20.00
21 11943 21.00
22 11420 22.00
23 10923 23.00
24 10450 24.00
25 10000 25.00
26 9572 26.00
27 9165 27.00
28 8777 28.00
29 8408 29.00
30 8056 30.00
31 7721 31.00
109 Temperature Probe18