A, B, and C are constants provided by the thermistor manufacturer and derived from three
temperature test points.
R = Thermistor resistance in Ω.
T = Temperature in degrees K.
Important:
Use only a 5 kΩ 44007-type thermistor. This type thermistor has constants of A = 1.285e-3, B
= 2.362e-4, C = 9.285e-8. Using an incorrect type of thermistor can result in errors greater than 20 °C for
a temperature being measured of 100 °C.
For a detailed tutorial on temperature measurements, refer to Keysight Application Note 290
Practical
Temperature Measurements
available at
For the TCouple Probe Type...
The
TCouple
probe types allows these settings:
Type
: Select the type of thermocouple. Supported types are J (default), K, E, T, N, or R
Reference
: Thermocouple measurements require a reference junction temperature. You can input a
known fixed reference junction temperature (typically used for external reference junctions) or use the
internally measured temperature of the front terminals as the reference junction temperature. Select
internal or fixed reference.
Important:
Since the internal reference temperature is the temperature of the
front
connections, use of
the
rear
connections with the selection of the internal reference junction will have an unknown error with
no specified performance and is not recommended.
Offset Adjust
: Allows you to make minor temperature adjustments to correct for the differences between
the DMM internal temperature measurement of the front connection and the actual temperature of the
measurement terminals. When you select the internal reference junction, the internal temperature meas-
urement of the front terminals plus the specified offset value is used as the reference junction temperature.
For example, if the measured internal temperature is +20.68 °C and the specified offset is +5 °C, the arti-
ficial cold junction mathematics uses the sum of the two values. Keysight recommends that the offset be
left at 0 unless metrology has indicated otherwise.
Fixed Offset
: When you select the external reference junction, you must specify the reference junction
temperature in degrees Celsius. Enter a value from -20 °C to +80 °C. Default: 0 °C. For example, to set the
fixed reference temperature to +23.36 °C:
Press
Done
to return to the main temperature menu showing additional settings for thermocouple meas-
urements:
Features and Functions
74
Keysight True
volt
Series Operating and Service Guide
