Control Elements - Hameg HM8012 Service Manual

C o n t r o l E l e m e n t s

Control Elements

DISPLAY (7-segment LED + LED)
The digital display shows the measurement value with 4¾ digit
resolution, in which the largest fi gure is used up to "5". It will
also display various warning messages. The measurement
value will be displayed with decimal points and polarity sign.
For DC measurement, a minus sign will appear in front of the
fi gures when the positive polarity of the measured value is
connected to the COM input
(LED)
Indicator denoting validation of the audible continuity test si-
gnal. When used as an ohmmeter, the audible signal triggers
when the measured resistance value is less than 0.1% of the
range or 50 counts. For other functions, the indicator is hid-
den.
BEEP (pushbutton)
Pushbutton for activating the audible signal.
A (safety terminal for 4 mm banana plugs)
Connection (high potential) for DC and AC current measure-
ments in the 10 A range in conjunction with the COM input
(low potential).
Current in excess of 10 A (max. 20 A) must not be
applied for a period exceeding 30 s, otherwise the
internal measurement resistor thermal device will
blow.
mA (safety terminal for 4 mm banana plugs)
Connection (high potential) for DC and AC current measure-
ments up to 500 mA in conjunction with COM input
tential). The input is fuse-protected.
HOLD (LED)
Indicator denoting that the displayed value has been frozen.
The function can be activated using key
pressing the HOLD/OFFSET key.
COM (safety terminal for 4 mm bana plugs)
The COM terminal (low potential) is the common connector for
6
Subject to change without notice
.
(low po-
. Deactivation is by
all the measurement functions to which the potential close to
the ground of the measured quantity will be applied.
For safety reasons, the voltage across this ter-
minal compared to the case (guard wire, ground)
shall be 250 V at most.
OFFSET (LED)
Indicator denoting that the displayed value is a relative measu-
rement. The displayed value corresponds to the input value
less the value present on the display during initial action on
the HOLD/OFFSET key . Activate this function by means of a
second press on the HOLD/OFFSET key.
V/Ω/T°/dB/
(safety terminal for 4 mm banana plugs)
Connection (high potential) for measurements of voltages,
resistances, temperatures and diode junctions in conjunction
with the COM input (safety terminal).
For safety reasons, the voltage across this ter-
minal compared to the case (guard wire, ground)
shall be 600 V at most.
DC
HOLD/OFFSET (pushbutton)
Pushbutton for validating the HOLD or OFFSET functions. Pres-
sing the key the fi rst time will freeze the front panel display.
The HOLD indicator then lights up. The AUTO, AC-DC, BEEP,
and keys are inoperative.
A second press gives access to the relative mode. The value
memorized by the HOLD function is then subtracted from each
measurement before being displayed. The OFFSET indicator
lights up.
A third press will freeze the relative value. The HOLD
OFFSET indicators light up. A fourth press will delete the
HOLD and OFFSET mode.
(pushbutton)
Pushbutton for changing to a lower range. On each press, the
new range is displayed fl eetingly on the display in code form
(L1 for lowest range, L2 for second range, etc.).
(pushbutton)
Pushbutton for changing to a higher range. Each time pressed,
the new range will be displayed fl eetingly on the display in code
form (L1 for lowest range, L2 for second range, etc.).
and