Campbell Scientific CR9000X Measurement and Control System - Manual (Page 231)

Section 7. Measurement Instructions
7-7
Although all range codes are shown in the table, due to resolution issues, not
all range codes are usable.
CR9050/CR9051E modules: only the 50 mV and 200 mV voltage ranges
should be used. The 200 mV range basic resolution is 6.3 uV which
corresponds to ~0.3 degrees F using Type T thermocouples.
CR9058E: Only the 2 volt range should be used. Its basic resolution is 10
uV which corresponds to about 0.5 degrees F using Type T thermocouples.
CR9055(E): It is not recommended to use this module for thermocouple
measurements. It does not have a reference RTD, and the best basic
resolution, using the 500 mVolt range, is 16 uV which corresponds to a
resolution of about 0.8 degrees F when using Type T thermocouples.
Place an R at the end of the range code (ex: 50mVCR) in order to perform an
Input Voltage Limit check before making the measurement. If the input is out
of Input Voltage Limit, a NAN will be returned.
See Section 3.1.2.2 Differential Voltage Range for R, Input Limit check,
option.
Enter -1, -2, -3, -4 or -5 for the integration parameter when using a
CR9058E and the filter order will be set to 1, 2, 3, 4, or 5. The
integration time will be set to the maximum allowed for the given Scan
Interval and filter order.
See Section 3.2 CR9058E Isolation Module Measurements for details.
See Section 3.1.4 for a study of TC measurements and error analysis.
See Section 3.1.2.2 Differential Voltage Range for in-depth coverage of the
Differential Measurement process.
TCSE (Dest, Reps, Range, ASlot, SEChan, TCType, TRef, SettlingTime,
Integ, Mult, Offset)
S.E. Chanel
Ground
Thermocouple
This instruction measures a thermocouple with a single-ended voltage
measurement and calculates the thermocouple temperature (
°C) for the
thermocouple type selected. The instruction adds the measured voltage to the
voltage calculated for the reference temperature relative to 0
° C, and converts
the combined voltage to temperature in °C.
Single Ended TC measurements are notorious for having issues
with ground offsets. For this reason, it is recommended to use
the TCDiff instruction and perform the measurement
differentially for the most accurate thermocouple measurement. NOTE
Range*:
R*:
CR9058E*: