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TECH
TIPS
RATOR
ENTER
MENU
200.0° C
Disconnect the process measurement sensor.
Connect the mini-connector from the test wires to the TC source
connection of the calibrator (figure above).
Connect the calibrator resistance measurement terminals to the
switch contacts to measure continuity.
Set the calibrator to source/simulate the correct thermocouple type
and to measure resistance.
Configure the calibrator for the switch test describing the expected
setpoint temperature, allowable deviation and expected deadband values.
Run the test and evaluate the test results.
Adjust the switch as needed and repeat the test, confirming that the
adjustment was successful and the switch is performing as expected.
•
When testing the tempera-
ture switch, the applied
temperature should agree
with the temperature
displayed on the controller
or switch’s display. If it does
not agree, the device’s
input A/D may need
adjustment per manufactur-
er’s procedure.
•
When testing a switch
with damping (delay of
output change for a change
on the input) set, it might
be necessary to test the
switch manually by slowly
changing the temperature
in small tests.
•
When testing a mechanical
temperature switch (no
external sensor), use a field
temperature bath calibrator
for best results.
•
To test live switch contacts
switching 24 V dc or 120-
240 V ac, select a calibrator
that can measure these live
voltages, such as the Fluke
75X family of Documenting
Process Calibrators.
Most other temperature
calibrators can only
measure continuity changes
when testing switches.
To perform the test:
To use a thermocouple simulator to test a switch
with a thermocouple input:
Additional resources
For more in depth information about
this application check out these videos
and application notes from Fluke.
Testing, troubleshooting, calibrating process
temperature devices
webinar
Testing a temperature switch with the Fluke 754
Process and temperature switch applications with
documenting process calibrators
Temperature calibration application note
Fluke temperature calibrators deliver high accuracy,
speed, and convenience
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Temperature Applications