28
GMC-I Messtechnik GmbH
V/Hz,
, Temperature,
and A/Hz Measurements
5.1.2 Alternating Voltage Measurement with 1 M
Load Resistance
and Frequency Measurement with Selectable Low-Pass Filter
(METRAHIT AM X-TRA / AM TECH / AM PRO / X-
TRA
/ O
UTDOOR
/ T
ECH
/
P
RO
/ SECULIFEHIT
AM
/
MD
only)
The measuring instrument includes a V
1M
switch position for
electricians with an input resistance of approximately 1 M
.
Erroneous displays resulting from capacitive coupling during
voltage measurement in power supply systems are reduced to a
minimum in this way.
Note
T
ECH
: see note in chapter 5.1.1.
➭
In accordance with the voltage to be measured, turn the rotary
switch to V~
1M
or
.
➭
Connect the measurement cables as shown.
The “
” connector jack should be grounded.
Voltage Measurement
Note
An intermittent acoustic signal warns the operator if the
measured value exceeds the upper range limit in the 1000 V
range.
Make sure that a current measuring range (“A”) has not been
activated when the multimeter is connected for voltage measure-
ment! If the fuse’s blowing limits are exceeded as a result of oper-
ator error, both the operator and the instrument are in danger!
➭
You can switch back and forth between voltage measurement
with and without low-pass filter.
➭
Press the
FUNC | ENTER
multifunction key repeatedly until unit of
measure V or V/Fil appears at the display.
Frequency Measurement
➭
Apply the measured quantity is the same way as for voltage
measurement.
➭
Manually select the measuring range for the voltage amplitude.
When the instrument is switched to frequency measurement,
the previously selected voltage measuring range remains
active.
➭
You can switch back and forth between frequency
measurement with and without low-pass filter.
Press the
FUNC | ENTER
multifunction key repeatedly until unit of
measure Hz or Hz/Fil appears at the display.
Lowest measurable frequencies and maximum allowable
voltages are included in chapter 8, “Technical Data”.
Measurement with Low-Pass Filter
Attention!
!
Be aware of the fact that dangerous voltage spikes are not
displayed during this type of measurement (see also “Voltage
Comparator”.
We recommend measuring voltage without the low-pass filter
first, in order to be able to detect any dangerous voltages.
A 1 kHz low-pass filter can be activated if required, in order to
filter out high frequency pulses of greater than 1 kHz, for example
when performing measurements at pulsed motor drives, i.e.
undesired voltages of greater than 1 kHz can be suppressed.
The active low-pass filter is indicated by the Fil display. The
multimeter is automatically switched to manual measuring range
selection.
1 kHz
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