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
H
L
AG
AG
H
L
AG
AG
H
L
AG
AG
E3
E3
AG
AG
G
G
AG
H
L
AG
H
L
AG
H
L
AG
E3
AG
G
G
G
G
G
G
12
V
12V
12
V
12V
SW
ITH
ED
SWITHED
12
V
12V
G
G
G
G
12
V
12
V
SW
ITH
ED
12
V
G 1
2V
G 12V
PO
W
ER
POWER
IN
IN
G 1
2V
PO
W
ER
IN
SE
RIA
L I
O
SERIAL I O
SE
RIA
L I
O
DIF
F
DIFF
SE
SE
SE
DIF
F
4
5
6
4
5
6
7
8
9
10
10
11
11
12
12
7
8
9
10
11
12
AG
AG
H
L
AG
AG
H
L
AG
AG
H
L
AG
AG
E2
E2
E1
E1
G
G
DIF
F
DIFF
AG
H
L
AG
H
L
AG
H
L
AG
E2
E1
G
G
DIF
F
1
2
3
1
2
3
1
2
3
4
5
6
1
2
3
4
5
6
SE
SE
SE
EA
RT
H
EARTH
EA
RT
H
G
5V
5V
5V
5V
P1
P1
P2
P2
C8
C8
C7
C7
C6
C6
C5
C5
C4
C4
C3
C3
C2
C2
C1
C1
G
5V
5V
P1
P2
C8
C7
C6
C5
C4
C3
C2
C1
SW
IT
HE
D
SWITHED
12
V
12V
CO
NT
RO
L
CONTROL
SW
IT
HE
D
12
V
CO
NT
RO
L
CR10
CR10
CR10
M
AD
E IN
U
SA
MADE IN USA
W
IR
IN
G P
AN
EL
N
O.
WIRING PANEL NO.
M
AD
E IN
U
SA
W
IR
IN
G P
AN
EL
N
O.
10
63
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
G
G
E3 AG
4
5
6
7
8
9
10
11
12
G G G G
12V 12V
SWITCHED
12V
G 12V
POWER
IN
SERIAL I/O
SE
DIFF
AG H L AG H
L AG H
L AG
G
G
E1 E2
1
2
3
1
2
3
4
5
6
G 5V 5V P1 P2
C8 C7 C6 C5 C4 C3 C2 C1
CONTROL
12V
SWITCHED
CR10
TCR
LT#3
4340
3
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+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)
Single-Ended Input; Red (1H)
