14
Änderungen vorbehalten / Subject to change without notice
(7) COMMON
(shock-proof socket for connectors
of 4mm diameter)
Connection (high potential) for voltage and
resistance measurements in combination with the
COMMON input
(5)
.
CAUTION!
The voltage across this terminal with
respect to case (non-fused earthed conductor,
ground) should not exceed 1000 V to ensure
safety of operation.
(8) DC/AC
(pushbutton)
Function selection between DC and AC
measurements.
(9)
(pushbutton)
Swich for disconnecting the acoustic signal. The
buzzer beeps with every change of the
measurement range, when overload occurs, and if
the display is zero in the resistance range.
(10) RANGE
(6-position rotary switch)
The range switch permits to adjust the
measurement ranges within the selected functions.
When voltages and currents of unknown magnitude
are measured,
firstly select the highest
measurement range!
Then set the switch to the
next range in order, until optimum resolution is
obtained.
(11) 10A
(20A) (shock-proof socket for connectors
of 4mm diameter)
Terminal (high potential) for AC and DC current
measurements in the 10A range in combination
with the common input
(5)
.
The input is not fuse
protected. At currents which exceed 10A (max.
20A) the maximum admissible measuring time
is 30 sec. Measuring times exceeding 30 sec.
can cause thermal damage of the internal
resistors.
Mode selection
A mode selection switch set serves to activate the
desired measurement function. Resistance,
currentand voltage measurements are selected
with mutually releasing switches. In the current
and voltage ranges, an additional selection between
AC and DC measurements is possible.
Range selection
The measurement ranges are subdivided into
decades. The full-scale values of the lowest ranges
are 0.2V, 0.2mA or 0.2k
Ω
, e.g. maximum full-scale
values of 199.99mV, 199.99
µ
A or 199.99
Ω
are
indicated. In the 20 M
Ω
and 10A ranges, a
maximum full-scale value of 19.999M
Ω
and
19.999A respectively is displayed. In all other
ranges, the measured values are indicated directly
in V, mA or
Ω
. When voltages or currents of
unknown magnitude are to be measured, firstly
select the highest measurement range, then switch
over to the range with the optimum display.
Indication of the measured value
The measured values are displayed by five 7
segment LED displays. The maximum value of the
first digit is “ 1 “, which corresponds to a 4
½
digit
display with a capacity of 19999 digits. The
measured value is indicated with correct point
position and sign. The digits are preceded by a mi-
nus sign, if the positive pole of the device under
test is connected to theCOMMON socket
(5)
in
case of DC measurement. If the input terminals
are short-circuited, a value of max. ± 2 digits
(according to the measurement range) is displayed.
If the full-scale value of the measurement range is
exceeded (or open input is used during resistance
measurements), the display will flash and indicate
”0” value. The buzzer beeps intermittently when
the resistance is near zero in the resistance ranges.
Test value application
The HM 8011-3 module is provided with four
shockproof connecting sockets, preventing
accidental contact with the measured quantity, if
adequate test cables (such as HZ 15) are used. To
ensure safety of operation, the test cables should
be checked for isolation damage periodically and
replaced, if necessary.
The COMMON socket
(5)
(black) is used for all
measurement ranges and accepts the earthy
potential for all measured quantities. Zero potential
and internal shielding of the HM8011-3 module are
connected to this terminal. The inputs
(3)
/
(11)
(blue) are exclusively reserved for current
measurements, whereas the V/k
Ω
input
(7)
serves
for all other types of measurement.
Voltage measurements
The maximum input voltage to the HM8011-3
with the COMMON socket connected to ground
potential is 1000 V, E.g.: If the HM8011-3 is con-
nected to the device under test, the sum resul-
ting from the test voltage and the voltage
across the COMMON terminal to ground should
nof exceed 1000 V. The maximum admissible
COMMON socket-ground potential difference
is 500 V
p
.
The mean value of the input voltage and AC
voltages are determined by the true rms value.
When measuring AC voltages, a DC component is
suppressed. If possible, the COMMON terminal
(5)
should be connected directly to ground or to
the test circuit point carrying the lowest potential
to ground.
During measurements of circuits containing
inductive components, inadmissibly high voltages
may occur, when the test circuit is opened. In this
case, appropriate precautions should be taken to
prevent destruction of the HIM 8011-3 module by
induced voltages.
