Campbell Scientific CR1000KD CR1000 Measurement and Control System - Page 310

Table 66., Limits of Error on CR1000 Thermocouple Polynomials, TCDiff, PanelTemp, Table 67.,

Page 310 highlights

Section 8. Operation Table 66. Limits of Error on CR1000 Thermocouple Polynomials TC Type Range °C Limits of Error °C Relative to NIST Standards -130 to 200 ±0.005 200 to 1000 ±0.02 K -50 -50 950 to 1372 to 950 to 1372 ±0.01 ±0.04 8.1.4.1.7 Reference-Junction Error Thermocouple instructions TCDiff() and TCSe() include the parameter TRef to incorporate the reference-junction temperature into the measurement. A referencejunction compensation voltage is computed from TRef as part of the thermocouple instruction, based on the temperature difference between the reference junction and 0°C. The polynomials used to determine the reference-junction compensation voltage do not cover the entire thermocouple range, as illustrated in tables Limits of Error on CR1000 Thermocouple Polynomials (p. 309) and ReferenceTemperature Compensation Range and Polynomial Error (p. 310). Substantial errors in the reference junction compensation voltage will result if the reference-junction temperature is outside of the polynomial-fit ranges given. The reference-junction temperature measurement can come from a PanelTemp() instruction or from any other temperature measurement of the reference junction. The standard and extended (-XT) operating ranges for the CR1000 are -25 to 50°C and -55 to 85°C, respectively. These ranges also apply to the referencejunction temperature measurement using PanelTemp(). Two sources of error arise when the reference temperature is out of the polynomial-fit range. The most significant error is in the calculated compensation voltage; however, a small error is also created by non-linearities in the Seebeck coefficient. Table 67. Reference-Temperature Compensation Range and Error TC Type Range °C Limits of Error °C1 T -100 to 100 ± 0.001 E -150 to 206 ± 0.005 J -150 to 296 ± 0.005 K -50 to 100 1Relative to ITS-90 Standard in NIST Monograph 175 ± 0.01 8.1.4.1.8 Thermocouple Error Summary Errors in the thermocouple- and reference-temperature linearizations are extremely small, and error in the voltage measurement is negligible. 310

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Section 8.
Operation
310
Table 66.
Limits of Error on CR1000 Thermocouple Polynomials
TC
Type
Range °C
Limits of Error °C
Relative to NIST
Standards
-130
to
200
±0.005
200
to
1000
±0.02
K
-50
to
1372
-50
to
950
±0.01
950
to
1372
±0.04
8.1.4.1.7 Reference-Junction Error
Thermocouple instructions
TCDiff()
and
TCSe()
include the parameter
TRef
to
incorporate the reference-junction temperature into the measurement. A reference-
junction compensation voltage is computed from
TRef
as part of the thermocouple
instruction, based on the temperature difference between the reference junction
and 0°C. The polynomials used to determine the reference-junction compensation
voltage do not cover the entire thermocouple range, as illustrated in tables
Limits
of Error on CR1000 Thermocouple Polynomials
(p. 309)
and
Reference-
Temperature Compensation Range and Polynomial Error
(p. 310).
Substantial errors
in the reference junction compensation voltage will result if the reference-junction
temperature is outside of the polynomial-fit ranges given.
The reference-junction temperature measurement can come from a
PanelTemp()
instruction or from any other temperature measurement of the reference junction.
The standard and extended (-XT) operating ranges for the CR1000 are -25 to
50°C and -55 to 85°C, respectively. These ranges also apply to the reference-
junction temperature measurement using
PanelTemp()
.
Two sources of error arise when the reference temperature is out of the
polynomial-fit range. The most significant error is in the calculated compensation
voltage; however, a small error is also created by non-linearities in the Seebeck
coefficient.
Table 67.
Reference-Temperature Compensation Range and Error
TC Type
Range °C
Limits of Error °C
1
T
-100 to 100
± 0.001
E
-150 to 206
± 0.005
J
-150 to 296
± 0.005
K
-50 to 100
± 0.01
1
Relative to ITS-90 Standard in NIST Monograph 175
8.1.4.1.8 Thermocouple Error Summary
Errors in the thermocouple- and reference-temperature linearizations are
extremely small, and error in the voltage measurement is negligible.