Fluke 45 - Manual (Page 40)

Operating the Meter From the Front Panel
Selecting A Function Modifier
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3-13
HOLD (Touch Hold) Modifier
The Touch Hold modifier allows you to take a measurement and "hold" that
measurement on the display. This feature can be particularly advantageous in difficult or
hazardous circumstances when you might want to keep your eyes fixed on the probes,
and then read the display when it is safe or convenient to do so. When a new, stable
reading is detected, a beep is emitted, and the display is automatically updated.
Press
H to select the Touch Hold modifier. When Touch Hold is selected, "HOLD" is
shown in the primary display. In Touch Hold, each press of
H forces a new reading to
be displayed. To exit Touch Hold, press down
H for two seconds.
If you are in the autorange mode when Touch Hold is selected, you will autorange to the
correct range. If you are in the manual range mode, you will enter Touch Hold in the
selected (fixed) range you were in when Touch Hold was selected.
The Touch Hold modifier can be combined with the MN MX modifier to hold and update
only when a new minimum or maximum value is detected. Pressing
H less that two
seconds when Touch Hold has been selected forces the display to update.
The meter allows you some choice when it comes to determining the minimum response
level needed for Touch Hold to capture and display a measurement. You can choose
among three Touch Hold sensitivity levels:
•
Level 1 (5 % of range)
•
Level 2 (7 % of range)
•
Level 3 (8 % of range)
To change this level, press
S, then press H . The number “1,” “2,” “ or “ 3 “appears
on the primary display. Press
U or T to step to the desired sensitivity level. Then
press
E to set the level and return the primary display. You can return to the primary
display without changing the sensitivity level by pressing any button except
E , U ,
or
T .
MN MX (Minimum Maximum) Modifier
The MN MX modifier causes the meter to store the minimum and maximum inputs
measured since the MN MX modifier was selected.
Press
J to select the MN MX modifier. When the MN MX modifier is first selected,
the minimum and maximum values are set to the displayed reading and the "MIN"
annunciator lights. Press
J again to display the maximum reading (and the "MAX"
annunciator). Each subsequent press of the
J button toggles between the minimum and
maximum measurements taken. To exit the MN MX modifier, press and hold down the
J button for two seconds.
Selecting the MN MX modifier turns off autoranging and locks in the present range.
Make sure you are in the correct range before selecting the MN MX modifier. If you
press
U or T after MN MX has been selected, you will automatically exit the MN
MX modifier.
To observe the quantity being measured without resetting the stored MN MX values, use
the secondary display by pressing
S , then select the same measurement function that
is selected for the primary display.
Using Function Modifiers in Combination
The meter allows you to use multiple function modifiers (dB, REL, HOLD, MN MX)
simultaneously. The selected modifiers are evaluated in the following order: HOLD, dB,
MN MX, and REL. That is, the meter first looks for a stable measurement for Touch