Simulated Rtd Temperature Verification - Tektronix KEITHLEY DMM6500 Calibration Manual

DMM6500 6½-Digit Multimeter with Scanning Calibration and Adjustment Manual
Simulated
temperature
–190 °C
0 °C
750 °C

Simulated RTD temperature verification

Use the following information to verify the performance of the DMM6500. Actual calibrator source
values will vary. RTD verification is based on the calibrator sourcing resistance and the DMM6500
conversion of the resistance measurement to calculated temperature based on the Callendar-Van
Dusen equation.
To verify RTD temperature accuracy, you will:
•
Apply accurate resistance from the calibrator to the terminals on the front panel of the DMM6500.
•
Verify that the displayed readings are within specified limits.
RTD equations
The temperature versus resistance readings listed in the RTD reference tables are calculated using
the Callendar-Van Dusen equation. There are two equations that are based on different temperature
ranges. There is an equation for the –200 °C to 0 °C range and one for the 0 °C to 850 °C range.
Equation for –200 °C to 0 °C temperature range
R = R [1 + AT + BT
RTD 0
where:
•
R is the calculated resistance of the RTD
RTD
•
R is the known RTD resistance at 0 °C
0
•
T is the temperature in °C
•
A = alpha [1 + (delta/100)]
•
B = –1 (alpha)(delta)(1E-4)
•
C = –1 (alpha)(beta)(1E-8)
The alpha, beta, and delta values are listed in the following table.
DMM6500-905-01 Rev. E June 2021
Uncompensated Lower limit
calibrator source
value (V)
–7.659 mV –190.2 °C
0.000 mV –0.2 °C
42.281 mV 749.8 °C
+ CT (T – 100)]
2 3
Section 2: Performance verification
Upper limit
–189.8 °C
0.2 °C
750.2 °C
2-21