Thermocouple limits of error – Campbell Scientific CR5000 Measurement and Control Module User Manual
Page 65
Section 3. CR5000 Measurement Details
3-11
Reference Temperature Errors Due to Panel Gradient
Chamber Changed From 80 to 25 °C at 1.3 °C/Minute
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
Time (minutes)
Measured - Actual (°C)
20
30
40
50
60
70
80
Chamber and CR5000 Panel Temperature (°C)
Channel 1
Channel 5
Channel 10
Channel 11
Channel 16
Channel 20
Panel
Chamber
FIGURE 4.3-3. Panel Temperature Gradients During 80 to 25 °C change
Thermocouple Limits of Error
The standard reference which lists thermocouple output voltage as a function
of temperature (reference junction at 0
o
C) is the National Institute of Standards
and Technology Monograph 175 (1993). The American National Standards
Institute has established limits of error on thermocouple wire which is accepted
as an industry standard (ANSI MC 96.1, 1975). Table 3.4-1 gives the ANSI
limits of error for standard and special grade thermocouple wire of the types
accommodated by the CR5000.
TABLE 3.4-1. Limits of Error for Thermocouple Wire (Reference Junction at 0
o
C)
Limits of Error
Thermocouple
Temperature
(Whichever is greater)
Type
Range
o
C
Standard
Special
T
-200 to 0
±
1.0
o
C or 1.5%
0 to 350
±
1.0
o
C or 0.75%
±
0.5
o
C or 0.4%
J
0 to 750
±
2.2
o
C or 0.75%
±
1.1
o
C or 0.4%
E
-200 to 0
±
1.7
o
C or 1.0%
0 to 900
±
1.7
o
C or 0.5%
±
1.0
o
C or 0.4%
K
-200 to 0
±
2.2
o
C or 2.0%
0 to 1250
±
2.2
o
C or 0.75%
±
1.1
o
C or 0.4%
R or S
0 to 1450
±
1.5
o
C or 0.25%
±
0.6
o
C or 0.1%
B
800 to 1700
±
0.5%
Not Estab.