Campbell CR10TCR User manual

CR10TCR THERMOCOUPLE REFERENCE
REVISION: 12/96
COPYRIGHT (c) 1995-1996 CAMPBELL SCIENTIFIC, INC.

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WARRANTY AND ASSISTANCE
The CR10TCR THERMOCOUPLE REFERENCE 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. To obtain a Returned Materials Authorization
(RMA), contact CAMPBELL SCIENTIFIC, INC., phone [phone]. 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:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
CAMPBELL SCIENTIFIC, INC. does not accept collect calls.
Non-warranty products returned for repair should be accompanied by a purchase order to cover the repair.
815 W. 1800 N.
Logan, UT 84321-1784
USA
Phone [phone]
FAX [phone]
www.campbellsci.com
Campbell Scientific Canada Corp.
11564 -149th Street
Edmonton, Alberta T5M 1W7
CANADA
Phone [phone]
FAX [phone]
Campbell Scientific Ltd.
Campbell Park
80 Hathern Road
Shepshed, Loughborough
LE12 9GX, U.K.
Phone [phone]
FAX [phone]

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1
CR10TCR THERMOCOUPLE REFERENCE
1. GENERAL
The Model CR10TCR Probe contains a
thermistor for measuring temperature and is
used as a reference temperature for
thermocouples measured with the CR10. It is
installed between the two terminal stripes in the
wiring panel. After all the thermocouples are
wired, the wiring panel cover is installed to
minimize temperature gradients on the terminal
strip.
1.1 SPECIFICATIONS
Temperature Measurement Range: -35°to +50°C
Thermistor Interchangeability Error: Typically
<±0.2°C over 0°C to 60°C ±0.4 @ -35°C.
Polynomial Linearization Error: <±0.5°C over
-35°C to +50°C.
2. ACCURACY −
−−
−TEMPERATURE
SENSOR
The overall probe accuracy is a combination of
the thermistor's interchangeability specification,
the precision of the bridge resistors, and the
polynomial error. In a "worst case" all errors
add to an accuracy of ±0.4°C over the range of
-24°to 48°C and ±0.9°C over the range of
-38°C to 53°C. The major error component is
the interchangeability specification of the
thermistor, tabulated in Table 1. For the range
of 0°to 50°C the interchangeability error is
predominantly offset. The bridge resistors are
0.1% tolerance with a 10 ppm temperature
coefficient. Polynomial errors are tabulated in
Table 2 and plotted in Figure 1.
TABLE 1. Thermistor Interchangeability
Specification
Temperature
Temperature (°C) Tolerance (±°C)
−40 0.40
−30 0.40
−20 0.32
−10 0.25
0 to +50 0.20
TABLE 2. Polynomial Error
-40 to +56 <±1.0°C
-38 to +53 <±0.5°C
-24 to +48 <±0.1°C
FIGURE 1. Error Produced by Polynomial Fit to Published Values

CR10TCR THERMOCOUPLE REFERENCE
2
3. INSTALLATION AND WIRING
The wiring diagram for the CR10TCR is shown
in Figure 1. The probe requires a single-ended
analog input channel and an excitation channel.
After the CR10TCR and thermocouple are
connected to the datalogger, install the wiring
panel cover (Figure 2 and 3).
CR10XTCR
LT#343403
FIGURE 2. Wiring Diagram
AG
AG
HLAG
AG
HLAG
AG
HLAG
AG
E3
E3
AG
AG
GG
AGHLAGHLAGHLAGE3AGGGGGGG12V
12V
12V
12V
SWITHED
SWITHED
12V
12V
GGGG12V12V
SWITHED
12V
G12V
G 12V
POWER
POWER
IN
IN
G12V
POWER
IN
SERIALI O
SERIAL I O
SERIALI O
DIFF
DIFF
SE
SE
SE
DIFF456
456
78910
10
11
11
12
12
789101112
AG
AG
HLAG
AG
HLAG
AG
HLAG
AG
E2
E2
E1
E1
GG
DIFF
DIFF
AGHLAGHLAGHLAGE2E1GG
DIFF123
123
123456
123456
SE
SE
SE
EARTH
EARTH
EARTH
G5V
5V
5V
5V
P1
P1
P2
P2
C8
C8
C7
C7
C6
C6
C5
C5
C4
C4
C3
C3
C2
C2
C1
C1
G5V5VP1P2C8C7C6C5C4C3C2C1
SWITHED
SWITHED
12V
12V
CONTROL
CONTROL
SWITHED
12V
CONTROL
CR10
CR10
CR10
MADEIN USA
MADE IN USA
WIRINGPANELNO.
WIRING PANEL NO.
MADEIN USA
WIRINGPANELNO.
1063
FIGURE 3. Wiring Panel, CR10TCR, and
Wiring Panel Cover
CAMPBELL
SCIENTIFIC
INC.
CR10
MADE IN USA
WIRING PANEL NO.
EARTH
DIFF
SE AG H L AG H L AG H L AG GGE3 AG
4 5 6
78 910 1112 GGGG 12V 12V SWITCHED
12V
G 12V
POWER
IN
SERIAL I/O
SE
DIFF AG H L AG H L AG H L AG GGE1 E2
1 2 3
12 34 56 G5V5VP1P2 C8C7C6C5C4C3C2C1
CONTROL
12V
SWITCHED
CR10TCR
LT#343403
FIGURE 4. CR10TCR Installed on the CR10
Wiring Panel
4. PROGRAMMING
Instruction 11 is used to measure the CR10TCR.
Instruction 11 provides AC excitation, makes a
single ended voltage measurement, and
calculates temperature with a fifth order
polynomial. A multiplier of 1.0 and an offset of
0.0 yields temperature in Celsius. For Fahrenheit,
use a multiplier of 1.8 and an offset of 32.
CAUTION: The reference temperature for
thermocouples must be in degrees Celsius.
EXAMPLE 1. Sample CR10 Instructions
01: P11 Temp 107 Probe
01: 1 Rep
02: 1 IN Chan
03: 3 Excite all reps w/EXchan 3
04: 15* Loc [:Ref_Temp]
05: 1 Mult
06: 0 Offset
* Proper entries will vary with program and
input location.
5. INSTRUCTION 11 DETAILS
Understanding the details in this section are not
necessary for general operation of the CR10TCR
with Campbell Scientific's dataloggers.
Instruction 11 outputs a precise 2 VAC excitation and
measures the voltage drop due to the sensor
resistance (Figure 5). The thermistor resistance
changes with temperature. Instruction 11 calculates
the ratio of voltage measured to excitation voltage
(Vs/Vx) which is related to resistance, as shown below:
Vs/Vx = 1000/(Rs+249000+1000)
where Rs is the resistance of the thermistor.
See the measurement section of the datalogger
manual for more information on bridge
measurements.
Instruction 11 then calculates temperature using a
fifth order polynomial equation correlating Vs/Vx with
temperature. The polynomial coefficients are given
in Table 3. The polynomial input is (Vs/Vx)*800.
Resistance and datalogger output at several
temperatures are shown in Table 4.
Black
Red
Clear
FIGURE 5. CR10TCR Reference Temperature
Schematics
Analog
Ground; Clear
Switched
Excitation;
Black (E3)
Sin
g
le-Ended In
p
ut; Red
(
1H
)

CR10TCR THERMOCOUPLE REFERENCE
3
TABLE 3. Temperature, Resistance, and
Datalogger Output
Temperature Resistance Output
°COHMS°C
-40.00 4067212 -39.18
-38.00 3543286 -37.55
-36.00 3092416 -35.83
-34.00 2703671 -34.02
-32.00 2367900 -32.13
-30.00 2077394 -30.18
-28.00 1825568 -28.19
-26.00 1606911 -26.15
-24.00 1416745 -24.11
-22.00 1251079 -22.05
-20.00 1106485 -20.00
-18.00 980100 -17.97
-16.00 869458 -15.95
-14.00 772463 -13.96
-12.00 687276 -11.97
-10.00 612366 -10.00
-8.00 546376 -8.02
-6.00 488178 -6.05
-4.00 436773 -4.06
-2.00 391294 -2.07
0.00 351017 -0.06
2.00 315288 1.96
4.00 283558 3.99
6.00 255337 6.02
8.00 230210 8.04
10.00 207807 10.06
12.00 187803 12.07
14.00 169924 14.06
16.00 153923 16.05
18.00 139588 18.02
20.00 126729 19.99
22.00 115179 21.97
24.00 104796 23.95
26.00 95449 25.94
28.00 87026 27.93
30.00 79428 29.95
32.00 72567 31.97
34.00 66365 33.99
36.00 60752 36.02
38.00 55668 38.05
40.00 51058 40.07
42.00 46873 42.07
44.00 43071 44.05
46.00 39613 46.00
48.00 36465 47.91
50.00 33598 49.77
52.00 30983 51.59
54.00 28595 53.35
56.00 26413 55.05
58.00 24419 56.70
60.00 22593 58.28
TABLE 4. Polynomial Coefficients
Coefficient Value
C0 -53.4601
C1 90.807
C2 -83.257
C3 52.283
C4 -16.723
C5 2.211
6. ELECTRICALLY NOISY
ENVIRONMENTS
AC power lines can be the source of electrical
noise. If the datalogger is in an electronically
noisy environment, the CR10TCR temperature
measurement should be measured with the AC
half bridge (Instruction 5) with the 60 Hz rejection
integration option on the CR10 (see Section 13
of the datalogger manual for more information
on noise). Instruction 11's fast integration will
not reject 60 Hz noise.
Example 2. Sample CR10 Instructions Using
AC Half Bridge
01: P5 AC Half Bridge
01: 1 Rep
02: 22 7.5 mV 60 Hz rejection Range
03: 1 IN Chan
04: 3 Excite all reps w/EXchan 1
05: 2000 mV Excitation
06: 15* Loc [:Ref_Temp]
07: 800 Mult
08: 0 Offset
02: P55 Polynomial
01: 1 Rep
02: 1* X Loc Air Temp
03: 15* F(X) Loc [:Ref_Temp]
04: -53.46 C0
05: 90.807 C1
06: -83.257 C2
07: 52.283 C3
08: -16.723 C4
09: 2.211 C5
* Proper entries will vary with program and
input location assignments.

CR10TCR THERMOCOUPLE REFERENCE
4
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