Fluke 50D Thermometer User Manual


 
Calibration
9
Table 3. Performance Test Values
Thermocouple Input Voltage Display Reading
Type (mV DC)
o
C
o
F
K -5.587 -182.0 ±(0.9) -295.6 ±(1.6)
K -3.211 -89.0 ±(0.8) -128.2 ±(1.4)
K 21.919 530.0 ±(1.2) 986.0 ±(2.3)
K 54.297 1355.0 ±(2.1) 2471.0 ±(3.8)
J -7.824 -197.0 ±(1.0) -322.6 ±(1.7)
J 13.997 258.0 ±(1.1) 496.4 ±(1.9)
J 39.442 705.0 ±(1.5) 1301.0 ±(2.7)
Calibration
When calibrating the thermometer, refer to Figure 5 for the proper setup connections and Figure 6 for
adjustment locations.
Caution
When directed to short a switch grid in the following procedures, use only the
elastomeric switch pad that is supplied as pca damage may occur if a hard tool
is used.
Thermometer Calibration
1. Turn the thermometer off and remove the top case leaving the Main PCA in the bottom case.
2. Simultaneously short the TP1 switch grid and turn on the thermometer by shorting the ON/OFF switch
grid. Hold the elastomeric switch pad on TP1 for at least 3 seconds after the thermometer turns on. This
puts the thermometer into the Thermocouple Calibration mode.
3. Allow the thermometer to stabilize at room temperature, 23
o
C ± 5
o
C (73
o
F ± 9
o
F).
4. Select
o
C mode. Select T1 if the thermometer is a Fluke 50D.
5. Adjust the 5520A for 0.00000V. Connect the 5520A output to the TP1 input.
6. Allow the thermometer reading to stabilize. Refer to Figure 6 and adjust the T1 offset adjustment (R7)
for a display reading of 25.2
o
C ± 0.1
o
C.
If you are calibrating a Fluke 50S, skip the next two steps.
7. Leave the 5520A adjusted for 0.00000 V. Connect the 5520A output to the T2 input and select the T2
function.
8. Allow the reading to settle and adjust the T2 offset adjustment (R13) for a display reading of 25.2
o
C ±
0.1
o
C.
9. Adjust the 5520A for 53.807 mV output.
10. Allow the reading to stabilize and adjust (R21) for a display reading of +1370.0
o
C ± 0.4
o
C.
11. Disconnect the thermometer from the 5520A. Turn the thermometer off by shorting the ON/OFF switch
grid.
12. With an elastomeric switch pad in both hands, use the left pad to short out the TP2 grid, and use the
right pad to first turn on the instrument and then quickly short out the VIEW switch grid. Hold this