Campbell Scientific IRTS-P User Manual

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IRTS-P Precision Infrared
Temperature Senso
Revision: 9/06
Copyright © 2002-2006
Campbell Scientific, Inc.

Warranty and Assistance

The IRTS-P PRECISION INFRARED TEMPERATURE SENSOR is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products. The customer shall assume all costs of removing, reinstalling, and shipping defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will return such products by surface carrier prepaid. This warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products which have been subjected to modification, misuse, neglect, accidents of nature, or shipping damage. This warranty is in lieu of all other warranties, expressed or implied, including warranties of merchantability or fitness for a particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special, indirect, incidental, or consequential damages.
Products may not be returned without prior authorization. The following contact information is for US and International customers residing in countries served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs for customers within their territories. Please visit www.campbellsci.com to determine which Campbell Scientific company serves your country. To obtain a Returned Materials Authorization (RMA), contact CAMPBELL SCIENTIFIC, INC., phone (435) 753-2342. After an applications engineer determines the nature of the problem, an RMA number will be issued. Please write this number clearly on the outside of the shipping container. CAMPBELL SCIENTIFIC's shipping address is:
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IRTS-P Table of Contents
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1. General Description.....................................................1
2. Specifications ..............................................................1
3. Installation....................................................................2
4. Wiring............................................................................3
5. Example Programs......................................................3
6. Maintenance...............................................................11
Figures
Tables
3-1. IRTS-P on UT018 Crossarm...................................................................2
3-2. Mounting IRTS-P to UT018 Crossarm...................................................2
5-1. Wiring for Example Programs ................................................................4
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IRTS-P Precision Infrared Temperature Sensor

1. General Description

An infrared temperature sensor (IRTS) is a non-contact means of measuring the surface temperature of an object by sensing the infrared radiation given off. IRTS are widely used for measurements of leaf, canopy, and average surface temperature. With contact sensors it is difficult to avoid influencing the temperature, maintain thermal contact, and provide a spatial average.
By mounting the infrared sensor at an appropriate distance from the target, it can be used to measure an individual leaf, a canopy, or any surface of interest.
The IRTS-P is an infrared temperature sensor calibrated to output the signal for the target temperature with the same output voltage as if a Type K thermocouple were sensing the target temperature. A separate type K thermocouple is used to measure the temperature of the sensor body. The sensor body temperature is used to correct the target temperature for greater accuracy.

2. Specifications

Power Requirements
Accuracy
Repeatability Mass Dimensions Response Time
Output Signal
Optics Wavelength Range Field of View
Operating Environment
None: self-powered
±0.3°C from -10° to 55°C (±0.1°C when sensor body and target are at the same temperature)
0.05°C from -10° to 55°C Less than 100 grams
6.3 cm long by 2.3 cm diameter Less than 1 second to changes in target temperature 2, type K, twisted, shielded pair thermocouple outputs (15 ft each), one for target temperature, one for sensor body temperature. The sensor body temperature is used to make a correction for target temperature. Silicon lens 6 to 14 micrometers 3:1 field of view (at 3 meters from sensor the FOV is a 1 meter diameter circle) Highly water resistant, designed for continuous outdoor use; temperature range:
-10° to 55°C
1
IRTS-P Precision Infrared Temperature Sensor

3. Installation

The field of view for infrared sensors is calculated based on the geometry of the sensor and lens. However, optical and atmospheric scatter and unwanted reflections from outside the field of view may influence the measurement. Under typical conditions, 80 to 90 percent of the IR signal is from the field of view and 10 to 20 percent is from the area surrounding the field of view. If the target surface is small, for example a single leaf, try to mount the sensor close enough that the surface extends beyond the field of view.
To obtain the desired view of the canopy or surface of interest, the IRTS-P is often mounted separately from a met station tower. A hole threaded for a standard tripod camera mount screw (1/4 inch diameter; 20 threads per inch) can be used to mount the sensor to a user-supplied support.
The IRTS-P can be mounted to a Campbell Scientific tripod or tower with the UT018 Crossarm (Figure 3-1.) A mounting kit (Stainless steel bolt, 2 washers, and 2 nuts PN 14475) is included with the IRTS-P that can be used to attach the sensor to the crossarm (Figure 3-2.)
FIGURE 3-1. IRTS-P on UT018 Crossarm
Tighten against sensor to fix angle of sensor.
Nut with two lock washers attaching bolt to the arm.
FIGURE 3-2. Mounting IRTS-P to UT018 Crossarm
2

4. Wiring

=
ATT
IRTS-P Precision Infrared Temperature Sensor
The IRTS-P has two thermocouple outputs. Each output is a pair of red and yellow wires. The pair labeled “Target” on the jacket near the wires is the output from the detector. The pair labeled “Body” is a thermocouple measuring the temperature of the sensor body. Previous versions of the sensor had a black band on the target cable to mark it. We recommend measuring the temperatures with differential voltage thermocouple measurements.
Target – Detector Temperature:
Target
Body
Yellow TC + Differential High Red TC – Differential Low
Bare - Ground
Sensor Body Temperature:
Yellow TC + Differential High Red TC – Differential Low Bare - Ground

5. Example Programs

The datalogger program to measure the IRTS-P measures the thermocouple outputs to obtain the IRTS-P sensor body tem perature a nd t he appa rent (uncorrected) temperature of the target.
The thermocouple temperature requires the temperature of the terminals to which the thermocouples are connected. The panel temperature is used as the reference for the CR23X, CR1000, and CR5000. The module temperature is not an accurate measurement of the CR10X panel temperature; a CR10XTCR is required to measure the reference temperature.
After measuring the thermocouple outputs, the sensor body temperature is used to calculate correction coefficients that are then used to correct the target temperature.
All three example programs measure the sensor once a second and output average values once an hour. The actual channels and outputs intervals need to be adjusted for the actual installation and application.
The equations implemented in the program are (Bugbee
Corrected Target Temperature, were
and Sensor Error Correction,
= Apparent Target Temperature,
2
KHATTPSEC = ;
et.al. 1996)
SECATTCTT
)))((/25.0(
SBSBSB
3
IRTS-P Precision Infrared Temperature Sensor
SB
and
00558.059237.09092.49 SBSBP
SB
SB
=SB
Sensor Body Temperature
00077.04248.02828.4 SBSBH
387.03816.50705.52 SBSBK
+=
++=
+=
2
2
2
The three example programs measure the sensor once a second and output average sensor and target temperatures once an hour. In an actual installation the measurement and output intervals, and channels used may be changed to accommodate the other measurements and outputs.
TABLE 5-1. Wiring for Example Programs
Sensor/Lead Description CR10X CR23X CR1000 CR10XTCR
Reference Temp:
Not Used
Not
Used Black Excitation E3 Red Signal SE1 Clear Ground AG
IRTS-P – Target/Black Band
Detector Temp Yellow TC + 2H 1H 1H Red TC - 2L 1L 1L
IRTS-P – Body/No Band
Sensor Temp Yellow TC + 3H 2H 2H Red TC - 3L 2L 2L Bare wire Shield G
4
CR10X Example Program
;{CR10X} ; *Table 1 Program 01: 1 Execution Interval (seconds)
;Measure CR10XTCR Reference Temperature
1: Temp (107) (P11) 1: 1 Reps 2: 1 SE Channel 3: 3 Excite all reps w/E3 4: 1 Loc [ RefTemp ] 5: 1.0 Mult 6: 0.0 Offset
;Measure IRt/c apparent target temperature
IRTS-P Precision Infrared Temperature Sensor
2: Thermocouple Temp (DIFF) (P14) 1: 1 Reps 2: 21 2.5 mV 60 Hz Rejection Range 3: 2 DIFF Channel 4: 3 Type K (Chromel-Alumel) 5: 1 Ref Temp (Deg. C) Loc [ RefTemp ] 6: 2 Loc [ AppTargT ] 7: 1.0 Mult 8: 0.0 Offset
;Measure Sensor Body Temp
3: Thermocouple Temp (DIFF) (P14) 1: 1 Reps 2: 21 2.5 mV 60 Hz Rejection Range 3: 3 DIFF Channel 4: 3 Type K (Chromel-Alumel) 5: 1 Ref Temp (Deg. C) Loc [ RefTemp ] 6: 3 Loc [ SenBodyT ] 7: 1.0 Mult 8: 0.0 Offset
;Calculate P, H, & K Coefficients
4: Polynomial (P55) 1: 1 Reps 2: 3 X Loc [ SenBodyT ] 3: 4 F(X) Loc [ Psb ] 4: 49.9092 C0 5: 0.59237 C1 6: 0.00558 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5
5: Polynomial (P55) 1: 1 Reps 2: 3 X Loc [ SenBodyT ] 3: 5 F(X) Loc [ Hsb ] 4: 4.2828 C0 5: 0.4248 C1 6: -0.00077 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5
6: Polynomial (P55) 1: 1 Reps 2: 3 X Loc [ SenBodyT ] 3: 6 F(X) Loc [ Ksb ] 4: 52.0705 C0 5: -5.3816 C1 6: 0.387 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5
5
IRTS-P Precision Infrared Temperature Sensor
;Calculate correction factor (SEC)
7: Z=1/X (P42) ; {1/Psb} 1: 4 X Loc [ Psb ] 2: 4 Z Loc [ Psb ]
8: Z=X*F (P37) ; {.25/Psb} 1: 4 X Loc [ Psb ] 2: 0.25 F 3: 4 Z Loc [ Psb ]
9: Z=X-Y (P35) ; {ATT - Hsb} 1: 2 X Loc [ AppTargT ] 2: 5 Y Loc [ Hsb ] 3: 5 Z Loc [ Hsb ]
10: Z=X*Y (P36) ; {ATT - Hsb}^2 1: 5 X Loc [ Hsb ] 2: 5 Y Loc [ Hsb ] 3: 5 Z Loc [ Hsb ]
11: Z=X-Y (P35) ; {subtract Ksb} 1: 5 X Loc [ Hsb ] 2: 6 Y Loc [ Ksb ] 3: 6 Z Loc [ Ksb ]
12: Z=X*Y (P36) ; {calculate SEC} 1: 4 X Loc [ Psb ] 2: 6 Y Loc [ Ksb ] 3: 7 Z Loc [ SEC ]
;Calculate corrected target temperature (CTT)
13: Z=X-Y (P35) ; 1: 2 X Loc [ AppTargT ] 2: 7 Y Loc [ SEC ] 3: 8 Z Loc [ CTT ]
14: If time is (P92) 1: 0 Minutes (Seconds --) into a 2: 60 Interval (same units as above) 3: 10 Set Output Flag High (Flag 0)
15: Real Time (P77) 1: 1220 Year,Day,Hour/Minute (midnight = 2400)
16: Average (P71) 1: 3 Reps 2: 1 Loc [ RefTemp ]
17: Average (P71) 1: 1 Reps 2: 8 Loc [ CTT ]
6
IRTS-P Precision Infrared Temperature Sensor
*Table 2 Program 02: 0.0000 Execution Interval (seconds)
*Table 3 Subroutines
End Program
-Input Locations­1 RefTemp 1 2 1 2 AppTargT 1 2 1 3 SenBodyT 1 3 1 4 Psb 1 3 3 5 Hsb 1 4 3 6 Ksb 1 2 2 7 SEC 1 1 1 8 CTT 1 0 1
CR23X Example Program
;{CR23X} ; *Table 1 Program 01: 1 Execution Interval (seconds)
;Measure Panel Reference Temperature
1: Panel Temperature (P17) 1: 1 Loc [ RefTemp ]
;Measure IRt/c apparent target temperature
2: Thermocouple Temp (DIFF) (P14) 1: 1 Reps 2: 21 10 mV, 60 Hz Reject, Slow Range 3: 1 DIFF Channel 4: 3 Type K (Chromel-Alumel) 5: 1 Ref Temp (Deg. C) Loc [ RefTemp ] 6: 2 Loc [ AppTargT ] 7: 1.0 Mult 8: 0.0 Offset
;Measure Sensor Body Temp
3: Thermocouple Temp (DIFF) (P14) 1: 1 Reps 2: 21 10 mV, 60 Hz Reject, Slow Range 3: 2 DIFF Channel 4: 3 Type K (Chromel-Alumel) 5: 1 Ref Temp (Deg. C) Loc [ RefTemp ] 6: 3 Loc [ SenBodyT ] 7: 1.0 Mult 8: 0.0 Offset
7
IRTS-P Precision Infrared Temperature Sensor
;Calculate P, H, & K Coefficients
4: Polynomial (P55) 1: 1 Reps 2: 3 X Loc [ SenBodyT ] 3: 4 F(X) Loc [ Psb ] 4: 49.9092 C0 5: 0.59237 C1 6: 0.00558 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5
5: Polynomial (P55) 1: 1 Reps 2: 3 X Loc [ SenBodyT ] 3: 5 F(X) Loc [ Hsb ] 4: 4.2828 C0 5: 0.4248 C1 6: -0.00077 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5
6: Polynomial (P55) 1: 1 Reps 2: 3 X Loc [ SenBodyT ] 3: 6 F(X) Loc [ Ksb ] 4: 52.0705 C0 5: -5.3816 C1 6: 0.387 C2 7: 0.0 C3 8: 0.0 C4 9: 0.0 C5
;Calculate correction factor (SEC)
7: Z=1/X (P42) ; {1/Psb} 1: 4 X Loc [ Psb ] 2: 4 Z Loc [ Psb ]
8: Z=X*F (P37) ; {.25/Psb} 1: 4 X Loc [ Psb ] 2: 0.25 F 3: 4 Z Loc [ Psb ]
9: Z=X-Y (P35) ; {ATT - Hsb} 1: 2 X Loc [ AppTargT ] 2: 5 Y Loc [ Hsb ] 3: 5 Z Loc [ Hsb ]
10: Z=X*Y (P36) ; {ATT - Hsb}^2 1: 5 X Loc [ Hsb ] 2: 5 Y Loc [ Hsb ] 3: 5 Z Loc [ Hsb ]
8
IRTS-P Precision Infrared Temperature Sensor
11: Z=X-Y (P35) ; {subtract Ksb} 1: 5 X Loc [ Hsb ] 2: 6 Y Loc [ Ksb ] 3: 6 Z Loc [ Ksb ]
12: Z=X*Y (P36) ; {calculate SEC} 1: 4 X Loc [ Psb ] 2: 6 Y Loc [ Ksb ] 3: 7 Z Loc [ SEC ]
;Calculate corrected target temperature (CTT)
13: Z=X-Y (P35) ; 1: 2 X Loc [ AppTargT ] 2: 7 Y Loc [ SEC ] 3: 8 Z Loc [ CTT ]
14: If time is (P92) 1: 0 Minutes (Seconds --) into a 2: 60 Interval (same units as above) 3: 10 Set Output Flag High (Flag 0)
15: Real Time (P77) 1: 1220 Year,Day,Hour/Minute (midnight = 2400)
16: Average (P71) 1: 3 Reps 2: 1 Loc [ RefTemp ]
17: Average (P71) 1: 1 Reps 2: 8 Loc [ CTT ]
*Table 2 Program 02: 0.0000 Execution Interval (seconds)
*Table 3 Subroutines
End Program
-Input Locations­1 RefTemp 1 3 1 2 AppTargT 1 2 1 3 SenBodyT 1 3 1 4 Psb 1 3 3 5 Hsb 1 4 3 6 Ksb 1 2 2 7 SEC 1 1 1 8 CTT 1 1 1
9
IRTS-P Precision Infrared Temperature Sensor
CR1000 Example Program
'CR1000
Dim SB, Psb, Hsb, Ksb, SenEC Public PTemp_C, ATT_C, CTT_C
DataTable(IRTS-P,True,-1) DataInterval(0,60,Min,0) Average(1,ATT_C,IEEE4,0) Average(1,CTT_C,IEEE4,0) EndTable
BeginProg
Scan(1,Sec,1,0)
'Wiring Panel Temperature measurement PTemp_C:
PanelTemp(PTemp_C,_60Hz)
'IRTS-P Precision Infrared Temperature Sensor measurements ATT_C and CTT_C: 'Measure apparent target temperature with IRTS-P.
TCDiff(ATT_C,1,mV2_5C,1,TypeK,PTemp_C,True,0,_60Hz,1,0)
'Measure IRTS-P sensor body temperature.
TCDiff(SB,1,mV2_5C,2,TypeK,PTemp_C,True,0,_60Hz,1,0)
'Calculate Psb, Hsb, & Ksb coefficients.
Psb=49.9092+(0.59237*SB)-(0.00558*SB^2) Hsb=4.2828+(0.4248*SB)-(0.00077*SB^2) Ksb=52.0705-(5.3816*SB)+(0.387*SB^2)
'Calculate correction factor.
SenEC=(0.25/Psb)*((ATT_C-Hsb)^2-Ksb)
'Calculate corrected target temperature.
CTT_C=ATT_C-SenEC
CallTable(IRTS-P)
NextScan EndProg
10
IRTS-P Precision Infrared Temperature Sensor
CR5000 Example Program
Public RefT, TargetCorrT, TC(2), SensorCorr, Psb, Hsb, Ksb
Alias TC(1) = TargetApparentT Alias TC(2) = SensorBodyT
DataTable (AllDat,1,-1) DataInterval (0,60,Min,10) Average (1,RefT,FP2,0) Average (2,TC(),IEEE4,0) Average (1,TargetCorrT,IEEE4,0) EndTable
BeginProg Scan (1,Sec,3,0) PanelTemp (RefT,250) TCDiff (TC(),2,mV20C ,1,TypeK,RefT,True ,0,_60Hz,1.0,0) Psb = 49.9092 + 0.59237 * SensorBodyT - 0.00558 * SensorBodyT^2 Hsb = 4.2828 + 0.4248 * SensorBodyT - 0.00077 * Sensor B ody T^2 Ksb = 52.0705 - 5.3816 * SensorBodyT + 0.387 * SensorB odyT^2 SensorCorr = (0.25/Psb) * ((TargetAppare ntT - Hsb)^2 - Ksb) TargetCorrT = TargetApparentT - SensorCorr CallTable Alldat
NextScan EndProg

6. Maintenance

As with any optical sensor, it is important to keep the lens and view clean. Otherwise the sensor will be measuring the temperature of the obstruction instead of the surface of interest.
Clean the lens gently with a moistened cotton swab. Distilled water or alcohol works well for most dust/dirt. Salt deposits dissolve better in a weak acid solution (~0.1 molar).
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IRTS-P Precision Infrared Temperature Sensor
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