Uniformity Alignment 1St Iteration - Fluke 9190A Operator's Manual

UUT Number of
SETPOINT °C Samples
140 °C 40
100 °C 40
25 °C 40
0 °C 40
−45 °C
40
−95 °C
40
SETPOINTS °C
140 °C
0 °C
−95 °C

Uniformity Alignment 1st Iteration

st
Perform the 1 Uniformity Alignment as follows:
1. Set the UUT SETPOINT temperature to -90 °C and engage the temperature control.
2. Monitor the Stability Status indicator to ensure the heat source is stable. Let the UUT
soak at the -90 °C SETPOINT for 45 minutes after the Stability Status indicator
shows that the temperature is stable (flat line). Measure the ACTUAL gradient,
which is the temperature of the secondary PRT (30 mm probe) minus the temperature
of the primary PRT (0 mm probe). Take the average of 40 samples for each of the
probes. Calculate as follows:
ACTUAL grad = T
3. Query the UUT gradient sensor reading with this serial command:
SOUR:SENS:GRAD:DATA?
4. Repeat this 40 times to get an average of the gradient sensor reading. This value is
called "UUT grad". Calculate the Error with this formula:
ERROR = UUT grad – ACTUAL grad
1
5. If the magnitude of ERROR
temperature and repeat the Uniformity Alignment 1
6. Query the UUT GRAD 1 calibration parameter as follows:
SOUR:SENS:CAL:GRAD1?
7. Grad 1 is associated with UUT block temperature -90 °C. Calculate the new Grad 1
calibration parameter as follows:
New = GRAD 1 – ERROR
GRAD 1
Table 4-4. As Found Uniformity Results
Average PRT
Secondary
Reading °C
Table 4-5. As Found Stability Specifications
Stability 2σ Spec (±°C)
0.015 °C
0.015 °C
0.015 °C
- T
30 0
is less than 0.012, skip to the next Gradient calibration
1
1
Uniformity
Average PRT Error °C =
Primary °C PRTsec-
PRTprim
Soak Time
(minutes)
45
45
45
st
Iteration procedure.
Calibration
Temperature Source Calibration
Specification
°C
0.05 °C
0.05 °C
0.05 °C
0.05 °C
0.05 °C
0.05 °C
Duration
(minutes)
30
30
30
4
4-9