Functions; Mode Selection; Range Selection; Measurement Value Display - Rohde & Schwarz Hameg HM8012 Manuel

F u n c t i o n s

Functions

Beginning in volt range (V) by using the keys
 and  you can step through all the mul-
timeter functions one by one, in following order:
– DC or AC voltages. Input on the V/Ω/T°/dB and
COM connectors.
– The measurement of DC or AC voltages in
decibels (reference 1 mW / 600 Ω ). Input to
V/Ω/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/Ω/T°/dB and COM con-
nectors.
– Temperature in degrees Celsius. Connection
of probe to V/Ω/T°/dB and COM connectors.
– Temperature in degrees Fahrenheit. Connec-
tion of probe to V/Ω/T°/dB and COM connec-
tors.
– Diode test. Inputs on V/Ω/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 func-
tion directly to any other function by a successive
series of pressings.

Mode selection

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

Range selection

In manual mode,  and  keys are used
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, then switch to the
range giving the most favorable display.
26
Subject to change without notice
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 emit-
ted repeatedly if it is selected. For the resistance
measurement function, the exceeding of the ca-
pacity (>50 MΩ ) 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
A is intended only for current measurements,
whereas the input V/Ω/T°/dB
other measurements. Each terminal is appropri-
ate to receive 4 mm banana plugs.
is common to all
and
is designed for all