Fluke 917X Series Technical Manual page 56

917X Series Metrology Wells
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Example:
A thermal switch opens and closes at about 100 °C, but the accuracy, repeatability, and
dead band of the switch need to be verified. The Switch program feature (described in
preceding sections) can be used to test the switch. Test results are shown on the main
screen during and after the test. To set up the test, do the following:
1. Connect the switch wires to the "Switch" terminals on the front of the
CAUTION: The switch, switch wires, switch components and/or switch
accessories can be damaged if the Metrology Well exceeds their temperature
limits.
2. Set up test "1" at MAIN|PROG MENU|SWITCH MENU|SETUP (see previous
NOTE: The LOW TEMP and HIGH TEMP in this example have been set to 100
°C ± 20 °C, but some switches may require a much wider window. The window
gives the instrument an approximation of where the switch will open and close.
If the window of LOW TEMP and HIGH TEMP is too narrow, the switch test
may abort before determining the characteristics of the switch.
NOTE: The APPROACH TEMP, RAMP RATE and CYCLES should be set such
that the highest desired accuracy of the switch temperatures is obtained.
APPROACH should not be set such that (HIGH TEMP – APPROACH) <=
LOW TEMP or "Settings conflict" is displayed when trying to start a switch test
and the test will not run.
NOTE: Depending on the mass and/or diameter the switch, there may be a
significant lag time in how fast the switch heats up or cools with respect to the
block of the Metrology Well. For larger mass and/or diameter switches, a lower
RAMP RATE (0.1-0.5 °C) and a higher APPROACH (5-10 °C) can produce
better results. More cycles may give a better average of when the switch opens
and closes, but a minimum of 2 cycles should be used when running a switch
test.
3. Select test "1" at MAIN|PROG MENU|SWITCH MENU|SELECT using the
4. Start the switch test at MAIN|PROG MENU|SWITCH MENU|RUN by
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Metrology Well (as described previously) and place the switch in the well.
Match the outside diameter of the switch with a similar sized hole of the
Metrology Well insert.
sections for more information on switch test setup). Set LOW TEMP to 80 °C,
HIGH TEMP to 120 °C, RAMP RATE to 1.0 °C, APPROACH to 5.0 °C, and
CYCLES to 3.
arrow keys and press "ENTER".
selecting Run and pressing "ENTER".