Functions; Mode Selection; Range Selection; Measurement Value Display - Hameg Instruments HM8012 Manual

F u n c t i o n s

Functions

Beginning in Volt-Range (V) by using the keys
18 and 19
you can step through all the
multimeter functions one by one, in following
order:
– DC or AC voltages. Input on the V/ /T°/dB and
COM connectors.
– The measurement of DC or AC voltages in
decibels (reference 1 mW / 600 ). Input to V/
/T°/dB and COM connectors.
– DC or AC current up to 500 mA. Inputs on
mA and COM connectors.
– DC or AC current, 10 A range. Inputs on the
A and COM connectors.
– Resistors. Inputs V/ /T°/dB and COM con-
nectors.
– Temperature in degrees Celsius. Connection
of probe to V/ /T°/dB and COM connectors.
– Temperature in degrees Fahrenheit. Connec-
tion of probe to V/ /T°/dB and COM connec-
tors.
– Diode test. Inputs on V/ /T°/dB and COM
connectors.
On each press, the new function is indicated by a
LED corresponding to the unit of the quantity to
be measured. It is possible to move from one
function directly to any other function by a
successive series of pressings.

Mode selection

For current and voltage modes, the AC-DC key 17
is used for choosing between DC voltage mea-
surement, AC or AC + DC true rms voltage
measurement.

Range selection

18 and
In manual mode,
for switching between the various measurement
ranges. The measurement ranges are split into
decades. After each range change, a code
appears indicating the new range being used.
This code is in LX form, where X is a value that
may vary from 1 to 6 depending on the range and
function and L1 is the lowest range. During
measurements of unknown voltages or currents,
first choose the highest measurement range,
28
Subject to change without notice
19 keys are used
then switch to the range giving the most favo-
rable display.
Change to the higher range is obtained when the
value exceeds 51,000 counts. Change to the lower
range is obtained when the value drops below
4,900 counts. It is possible to know which range
has been selected by the unit by temporarily
deactivating the AUTO mode so that the range
indication code appears fleetingly.

Measurement value display

Measurement values are represented by 7 seg-
ment LED's display associated with one LED for
the negative sign. The maximum value of the 1st
digit is 5; this corresponds to a 4¾ digit display
with a 50,000 counts measurement capacity. A
minus sign appears in front of the figures when,
during DC measurements, the positive polarity
of the measured value is on the COM terminal
With the inputs short-circuited, the display
indicates (depending on the measurement range)
value zero ±2 digit. When the range is overrun,
the display shows "OFL" and an audible beep is
emitted repeatedly if it is selected. For the
resistance measurement function, the exceeding
of the capacity (>50 M ) generates the "OPEN"
message.
If the multimeter is not connected to a circuit,
the display indicates random values due to the
very high input impedance for ranges of 500 mV
and 5 V.

Measurement inputs

The HM8012 has four safety terminals with which,
when using appropriate measurement cables (e.g.
HZ15), unintended contacts with the measurand
are nearly impossible. As a safety measure the
measurement cables should be checked periodi-
cally for insulation faults and, when necessary, be
replaced. The "COM" terminal
the measurement ranges. The potential close to
ground of all the measurement quantities should
be applied to this terminal. The input mA
is intended only for current measurements,
whereas the input V/ /T°/dB
other measurements. Each terminal is appropriate
to receive 4 mm banana plugs.
.
is common to all
and A
is designed for all