Amprobe AM91RS User Manual

USER'SUSER'S

MANUALMANUAL

AM91RS

AMPROBE

A United Dominion Company

1

1) SAFETY

This manual contains information and warnings that must be followed for operating the
meter safely and maintaining the meter in a safe operating condition. If the meter is used
in a manner not specified by the manufacturer, the protection provided by the meter may
be impaired. The meter is intended only for indoor use.

The meter meets the requirements for double insulation to IEC61010-1(1995), EN61010­1(1995), UL3111-1(6.1994), CSA C22.2 NO. 1010-1-92 to terminals:
V/R : Category IV 600V ac and dc, and Category III 1000V dc and 750V ac.

mA/µA : Category III 500V ac, and Category II 300V dc.
A : Category III 600V ac, and Category II 300V dc.

PER IEC61010 OVERVOLTAGE INSTALLATION CATEGORY

OVERVOLTAGE CATEGORY I

Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in
which measures are taken to limit the transient overvoltages to an appropriate low level.
Note – Examples include protected electronic circuits.

OVERVOLTAGE CATEGORY II

Equipment of OVERVOLTAGE CATEGORY II is energy-consuming equipment to be
supplied from the fixed installation.
Note – Examples include household, office, and laboratory appliances.

OVERVOLTAGE CATEGORY III

Equipment of OVERVOLTAGE CATEGORY III is equipment in fixed installations.
Note – Examples include switches in the fixed installation and some equipment for
industrial use with permanent connection to the fixed installation.

OVERVOLTAGE CATEGORY IV

Equipment of OVERVOLTAGE CATEGORY IV is for use at the origin of the installation.
Note – Examples include electricity meters and primary over-current protection
equipment.

2

TERMS IN THIS MANUAL

WARNING identifies conditions and actions that could result in serious injury or even

death to the user.

CAUTION identifies conditions and actions that could cause damage or malfunction in

the instrument.

WARNING

To reduce the risk of fire or electric shock, do not expose this product to rain or moisture.
To avoid electrical shock hazard, observe the proper safety precautions when working
with voltages above 60 VDC or 30 VAC rms. These voltage levels pose a potential shock
hazard to the user. Do not touch test lead tips or the circuit being tested while power is
applied to the circuit being measured. Keep your fingers behind the finger guards of the
test leads during measurement. Inspect test leads, connectors, and probes for damaged
insulation or exposed metal before using the instrument. If any defects are found, replace
them immediately. Do not measure any circuit that draws more than the current rating of
the protection fuse. Do not attempt a current measurement where the open circuit voltage
is above the protection fuse voltage rating. Suspected open circuit voltage can be
checked with voltage functions. Never attempt a voltage measurement with the test lead

inserted into the µA/mA or A input jack. Only replace the blown fuse with the proper
rating as specified in this manual.

CAUTION

Disconnect the test leads from the test points before changing functions. Always set the
instrument to the highest range and work downward for an unknown value if you are
using manual ranging mode.

INTERNATIONAL ELECTRICAL SYMBOLS

!!

Caution ! Refer to the explanation in this Manual

Caution ! Risk of electric shock
Earth (Ground)

Double Insulation or Reinforced insulation

3

Fuse

2) ELECTROMAGNETIC COMPATIBILITY (EMC)

The instrument meets EN55022(1994/A1; 1995/Class B) and EN50082-1(1992)

4

3) PRODUCT DESCRIPTION
Panel Illustration

1) 4-3/4 digits 40000 counts LCD
display

2) Push-buttons for special
functions & features

3) Selector to turn the Power On
or Off and Select a function

micro-amp current functions

4) Input Jack for 10A (20A for
30sec) current function

5) Input Jack for all functions
EXCEPT current (µA, mA, A)

functions

6) Common (Ground reference)
Input Jack for all functions

7) Input Jack for milli-amp and

5

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.

DC+AC True RMS

DC+AC True RMS is a term which identifies a DMM that responds accurately to the
total effective RMS value regardless of the waveforms such as: square, sawtooth,
triangle, pulse trains, spikes, as well as distorted waveforms with the presence of
harmonics and DC components. Harmonics and DC components may cause :

1)Overheated transformers, generators and motors to burn out faster than normal

2)Circuit breakers to trip prematurely

3)Fuses to blow

4)Neutrals to overheat due to the triplen harmonics present on the neutral

5)Bus bars and electrical panels to vibrate

Crest Factor

Crest Factor is the ratio of the Crest (instantaneous peak) value to the True RMS value,
and is commonly used to define the dynamic range of a True RMS DMM. A pure
sinusoidal waveform has a Crest Factor of 1.4. A badly distorted sinusoidal waveform
normally has a much higher Crest Factor.

NMRR (Normal Mode Rejection Ratio)

NMRR is the DMM's ability to reject unwanted AC noise effect which can cause
inaccurate DC measurements. NMRR is typically specified in terms of dB (decibel). This

product has a NMRR specification of 60dB at 50 and 60Hz, which means a good
ability to reject the effect of AC noise in DC measurements.

CMRR (Common Mode Rejection Ratio)

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 which can cause digit rattle or offset in voltage

measurements. This series has a CMRR specifications of 60dB 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.

6

4) OPERATION

ACV, ACV + Hz, & dBm + Hz functions
Defaults at ACV. Press SELECT button momentarily to select ACV + Hz. Press
SELECT button momentarily again to select dBm + Hz. Input sensitivity for Hz varies
automatically with voltage range selected in ACV + Hz function. It is designed especially

for measuring the frequency of high voltage noisy electrical signals.

Note: Default Reference impedance 600Ω will be displayed for 2 seconds before
displaying the dBm + Hz readings. Press dBm-ΩΩ (RANGE) button momentary to select

different reference impedance from 4, 8, 16, 32, 50, 75, 93, 110, 125, 135, 150, 200, 250,
300, 500, 600, 800, 900, 1000, up to 1200Ω. Impedance values will again be displayed for

2 seconds before displaying the dBm + Hz readings.

7

DCV, DC + AC V functions

Defaults at DC. Press SELECT button momentarily to select DC + AC. Analog bar­graph will be disabled in the DC + AC mode.

Hold

The hold function freezes the display for later view. Press the HOLD button momentarily
to activate and to exit the hold function

8

DC, AC, AC + Hz mV functions

Defaults at DC. Press SELECT button momentarily to select AC. Press SELECT button
momentarily again to select AC + Hz.

DC, AC, AC + Hz Adapter functions

The operation of Adapter function is similar to the mV function. Defaults at DC. Press
SELECT button momentarily to select AC. Press SELECT button momentarily again to

select AC + Hz. Adapter function is of extra high input impedance up to 1000MΩ, and
there is no decimal point on the digital display. It can cope with most voltage output
sensors/ transducers with the highest sensitivity and the least current drain.