Fluke 9105, 9107

HoLd=OFF Hold mode set to off

Tochange the mode press “UP” or “DOWN”.

HoLd=Aut Automatic mode

HoLd=n.c. Normally closed mode

HoLd=n.o. Normally open mode

Press “SET” to accept the displayed setting.

8.5.3 Scan Hold

In addition to controlling the hold temperature display,a switch can also con-

trolset-point scanning by enabling the scan hold function. When the switch

changes from its normal position to its activep osition scanning will stop. For

the scan holdto be effective scanning must be enabled and the scan rate should

be set to a relativelylow value (see sections 8.4.1 and 8.4.2).

The scan holdis set in the primary menu after the temperature hold mode

setting.

SHoLd=OF Scan hold set to off

Tochange the mode press “UP” or “DOWN”.

SHoLd=On Scan hold set to on

Press “SET” to accept the displayed setting.

8.5.4 Switch Wiring

The thermal switch or cut-out is wired to the calibrator at the two terminals at

the back of the dry-well calibrator labeled “DISPLAYHOLD”. The switch

wires may be connected to the terminals either way.Internally the black termi-

nal connectsto ground. The red terminal connects to +5V through a 10 kΩre-

sistor.The calibrator measures the voltage at the red terminal and interprets

+5V as open and 0V as closed.

8.5.5 Switch TestExample

This section describes a possible application for the temperature hold feature

and howthe instrument is set up and operated.

Suppose you havea thermal switch which is supposed to open at about 75°C

and close atabout 50°C and you want to test the switch to see how accurate and

repeatableit is. You can use the temperature hold feature and the ramp and

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8Controller Operation