Common mode voltage is voltage present on both
the COM and VOLTAGE input terminals of a DMM,
with respect to ground. CMRR is the DMM's ability
to reject common mode voltage effect that can
cause digit rolling or offset in voltage measure-
ments. This series has a CMRR specifications of
> 80dB at DC to 60Hz in ACV function; and
> 120dB at DC, 50 and 60Hz in DCV function. If
neither NMRR nor CMRR specification is specified,
a DMM's performance will be uncertain.
NMRR is the DMM's ability to reject unwanted AC
noise effect that can cause inaccurate DC
measurements. NMRR is typically specified in
terms of dB (decibel). This series has a NMRR
specification of > 60dB at 50 and 60Hz, which is a
good and definite ability to reject the effect of
noise when making DC measurements.
NMRR (Normal Mode Rejection Ratio)
CMRR (Commaon Mode Rejection Ratio)
The analog bar graph provides a visual indication of
measurement like a traditional analog meter
needle. It is excellent in detecting faulty contacts,
identifying potentiometer clicks, and indicating
signal spikes during adjustments. Analog bar-
graph is not available in AC+DC True RMS Voltage
& Current modes.
Analog bar-graph
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In AC Voltage, press
SELECT
button momentarily
to toggle between AC and dBm. In DC Voltage,
press
SELECT
button momentarily to toggle
between DC, and DC+AC. In mV Voltage, press
SELECT
button momentarily to select DC, AC, or
DC+AC.The new settings will be saved
automatically to the non-volatile memory as
power up default. In DCV and DCmV, press
500000
button momentarily to toggle between
4-4/5 digits and 5-4/5 digits readings. In voltage or
current functions, press the
~Hz
push button
momentarily to activate or to exit Line Level
Frequency measuring function. Line Level
Frequency measuring function is designed
especially for noisy electrical high voltage signals.
6) OPERATION
AC Voltage, DC Voltage, DC+AC Voltage, &
~Hz Line Level Frequency
CAUTION
Before and after hazardous voltage measurements,
test the voltage function on a known source such
as line voltage to determine proper meter
functioning.
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