43
Subject to change without notice
STOP
M e n u s t r u c t u r e
The autorange function is to be used with care. For
measurements on high impedance source and
measurement voltages in the range (90%) of full
scale 1 V, changing to a higher range is possible
with activated AUTO function. The HM8112-3 has
an input impedance of 10M
Ω
in the 10 V range
instead of 1 G
Ω
in the 1 V range. By loading a high
impedance source of several 100 M
Ω
with by input
impedance of 10 M
Ω
the measurement result will
be errouneous.
Menu structure
Menu prompting
From every measurement function the menu can be entered
by pressing MENU
18
. Within the menu, every button which
can be used is illuminated. The menu can be always left by
pressing ESC
19
without acceptance of entered values.
Call of the menu by MENU
18
.
Choice of menu item with
20
and
23
. The menu item is
opened with MENU
18
or branch to the next menu level.
Selection of parameters shown with
20
and
23
.
Acceptance of parameters changed with MENU
18
. If the menu
is left, the instrument will return to the last measurement
function.
19
ESC
Leaving the menu. Return to the last measuring function
without acceptance of the value entered.
20
Rotating menu prompting. Jump to the next menu item with
every key operation. On reaching the last menu item the display
continues with the first menu item.
23
Rotating menu prompting. Jump to the previous menu item
with every key operation. On reaching the first menu item the
display will roll over and continue with the last menu item.
22
ENTER
Use this button only in the logger menu „6:Logger.“ Switching
to the next buffered value by every key operation or acceptance
of an input.
Menu structure and function
The menu will be accessed by pressing MENU
18
. It branches
to the submenues described below.
0:Time
The time intervals between the measurements are adjustable
from 0.01 s to 60 s. That means, a reading is taken every 0.01 s
or only every 60 s.
The sampling rate can assume the following values:
10 ms
(only via interface)
50 ms
(only via interface)
100 ms
(default setting after switch-on)
500 ms
1 s
10 s
60 s
That means, for example, that every 500 ms a measurement
is taken and the value is updated in the display. After switch-
on a value of 100 ms will be preset. Removal of the line voltage
will not save a selected value.
If the measurement function is changed, the HM8112-3
assumes the default sampling rate, unless a sampling rate
between 10 s and 60 s is chosen. Then changing the measuring
function sets the sampling rate automatically to 1 s.
Example:
The sampling rate for V
DC
is set to 60 s. Then the
function A
DC
is selected. The instrument will reduce the
sampling rate automatically to 1 s. The new sampling rate
applies to all functions. If a sampling rate greater than 1 s is
needed, it has to be selected after every change of function.
A sampling rate of 60 s means:
The HM8112-3 integrates the input voltage and the
the reference voltage over a period of 60 s. After
expiry of this time the value calculated will be
displayed.
1:Filter
Selection of the number of values taken for averaging. In case
of selection of a number greater than 1, the selected number
will be taken for averaging. By calculating a new averaged
value, the first measured value will be discarded and the mean
value will be computed.
OFF
(default setting after switch-on)
2
4
8
16
2:Temp
In this menu item the dimension for the temperature measure-
ment is selected.
° C
Degrees Celsius
° F
Degrees Fahrenheit
The dimensions selected last will be saved even if the mains
will be turned off.
3: Sensor
Here the temperature sensor used is selected.
After switch on of the HM8112-3 and selection of the menu item
“3:Sensor“, if a measurement function other than temperature
measurement was set, PT 100 as temperature sensor is selected
by default. If the thermocouple is chosen the HM8112-3 is in
measurement function
15
ϑ
TH.
Also the instrument will return to the measurement function
13
ϑ
PT after selection of the PT-sensor. The sensor type
selected last will be stored in the instrument even if the main
voltage is turned off.
–
K–type: thermocouples NiCr-Ni (default setting after
switch-on)
–
J–type: thermocouples Fe-CuNi
–
PT1000: platinum resistance sensor with R
0
= 1000
Ω
–
PT100: platinum resistance sensor with R
0
= 100
Ω
(default
setting after switch-on)
Comp
For measurements with thermocouples a reference with a
known temperature must be defined. This reference tempera-
ture is provided to the HM8112-3. Therfore 3 methods are
possible:
HINT
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