Fluke 9190A - Accuracy Alignment

9190A
Operators Manual
4-12
Accuracy Alignment
An Accuracy Alignment is a measurement of the UUT block temperature and then
comparing the error between what the primary PRT measures and what the UUT shows.
This is done for the three different temperatures specified.
Perform the Accuracy Alignment as follows:
1. Let the UUT soak at the 140 °C SETPOINT for 45 minutes. Send this serial
command to read the UUT display temperature:
SOUR:SENS:DATA?
2. Take the average of 40 samples of the UUT display temperature (UUT
DISP_TEMP
).
Take the average of 40 samples from the primary PRT (ACTUAL
TEMP
). Calculate as
follows:
NEW
OFFSET3
= OLD
OFFSET3
– (ACTUAL
TEMP
- UUT
DISP_TEMP
)
OLD
OFFSET3
= the current accuracy offset parameter stored in the UUT for the
140 °C point.
3. Enter the NEW
OFFSET3
value calibration parameter into the UUT from the front panel:
MENU > SYSTEM MENU > CALIB > CAL POINTS > TEMP_3 or send these
serial commands:
SYST:PASS:CEN <password>
SOUR:SENS:CAL:PAR3 XXX.XXX
4. Repeat the procedure for these UUT block temperatures:
• 0 °C
• -90 °C
• 0 °C
5. Measure the 0 °C point twice, once descending in temperature, and once ascending in
temperature.
6. Take the average of the two 0 °C data sets for the (Block
TEMP
) value when calculating
the accuracy offset parameter. Use this equation:
NEW
OFFSET2
= OLD
OFFSET2
–
ACTUAL
TEMP
– (UUT
DISP TEMP U
P
+ UUT
DISP TEMP DOW
N
)
2
7. Use Table 4-6 to determine the correct calibration parameter to adjust for each of the
SETPOINT temperatures.
Table 4-6. Accuracy Calibration Parameter Serial Commands
Temperature Calibration Parameter Serial Command
−90 °C TEMP
1
SOUR:SENS:CAL:PAR1[?]
0 °C TEMP
2
SOUR:SENS:CAL:PAR2[?]
140 °C TEMP
3
SOUR:SENS:CAL:PAR3[?]