Fluke 5500A, Service Manual

Page: 85 / 296

Calibration and Verification
Performance Verification Tests
3
3-31
3-36. Thermocouple Measurement Accuracy
The Thermocouple Measurement Accuracy test checks the internal temperature
reference. To perform this test, measure a lag bath temperature 2
°
C of the
5500A. Set the 5500A to Internal Reference, J thermocouple type. Make connections
with J-type thermocouple wire as shown in Figure 3-1. Table 3-22 shows the test points.
Table 3-22. Thermocouple Measurement Accuracy Test
Nominal Value (
°
C) 5500A Reads (
°
C) Deviation
°
C 90-Day Spec. (
°
C)
Lag bath temperature 0.1
3-37. Thermocouple Sourcing Accuracy
The Thermocouple Sourcing Accuracy test checks the accuracy of the thermocouple
measuring circuitry. For this test, measure the dc output at the 5500A front panel TC
connector with a dc meter (observe polarity on the TC connector). Select External
Reference and the linear output 10
µ
V/
°
C as the thermocouple “type.” Use all copper
wires for these connections. The Fluke 5500A/Leads test lead kit contains a copper TC
plug and wire for this purpose. Table 3-23 shows the test points.
Table 3-23. Thermocouple Sourcing Accuracy Test
Nominal Value (
°
C) Equivalent Value
(mV)
Measured Value
(mV)
(TC connector)
Deviation
%
90-Day Spec.
(mV or %)
0 0.000 mV 0.003 mV
100 1.000 0.305%
-100 -1.000 0.305%
1000 10.000 0.035%
-1000 -10.000 0.035%
10000 100.000 0.008%
-10000 -100.000 0.008%
3-38. Thermocouple Measuring Accuracy
The Thermocouple Measuring Accuracy test checks the accuracy of the thermocouple
measuring circuitry. For this test, input a dc voltage into the 5500A front panel TC
terminals using copper plugs and wire (observe polarity on the TC connector), select
External Reference, and select the linear output 10
µ
V/
°
C as the thermocouple “type.”
The Fluke 5500A/Leads test lead kit contains a copper TC plug and wire for this
purpose. Table 3-24 shows the test points.
(Optional: You can also source a known temperature from a temperature calibrator using
a J-type thermocouple connection and Internal Reference. Source 0
°
C, 100
°
C, 1000
°
C,
and -200
°
C.)