Amprobe AM-140-A - Manual (Page 11)

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measurements. 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.
Analog bar-graph
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.
OPERATION
� CAUTION
Before and after hazardous voltage measurements, test the voltage
function on a known source such as line voltage to determine proper
meter functioning.
AC Voltage, DC Voltage, DC+AC Voltage, & Hz Line Level Frequency
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 nonvolatile
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.
Note: In dBm function, power up default reference impedance will be
displayed for 1 second before displaying the dBm readings. Press dBm-
(RANGE) button momentary to select different reference impedance of 4, 8,
16, 32, 50, 75, 93, 110, 125, 135, 150, 200, 250, 300, 500, 600, 800, 900, 1000, up
to 1200. The new impedance value will be saved automatically to the non-
volatile memory as power up default.