Brymen BM821s User manual

USER'S MANUAL
BM821s, BM822s, BM827s, BM829s
BM521s, BM525s

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1) SAFETY
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.
This manual contains information and warnings that must be followed for operating the
instrument safely and maintaining the instrument in a safe operating condition. If the
instrument is used in a manner not specified by the manufacturer, the protection provided by
the instrument may be impaired. The meter is intended only for indoor use.
The meter protection rating, against the users, is double insulation per IEC/UL/EN61010-1
Ed. 3.0, IEC/EN61010-2-030 Ed. 1.0, IEC/EN61010-2-033 Ed. 1.0, IEC/UL/EN61010-031
Ed. 1.1 and CAN/CSA-C22.2 No. 61010-1-12 Ed. 3.0 to Category IV 1000 Volts AC & DC.
Terminals (to COM) measurement category:
V / mAA / A : Category IV 1000 Volts AC & DC
Per IEC61010-1 2nd Ed. (2001) Measurement Category
Measurement Category IV (CAT IV) is for measurements performed at the source of the
low-voltage installation. Examples are electricity meters and measurements on primary
overcurrent protection devices and ripple control units.
Measurement Category III (CAT III) is for measurements performed in the building
installation. Examples are measurements on distribution boards, circuit- breakers, wiring,
including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation,
and equipment for industrial use and some other equipment, for example, stationary motors
with permanent connection to the fixed installation.
Measurement Category II (CAT II) is for measurements performed on circuits directly
connected to the low voltage installation. Examples are measurements on household
appliances, portable tools and similar equipment.

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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 current that exceeds the current rating of the protection
fuse. Do not attempt a current measurement to any circuit where the open circuit voltage is
above the protection fuse voltage rating. Suspected open circuit voltage should be checked
with voltage functions. Never attempt a voltage measurement with the test lead inserted into
the A/mA or A input jack. Only replace the blown fuse with the proper rating as specified in
this manual. Only use the test lead provided with the equipment or UL Listed Probe
Assembly rated CAT IV 1000V or better.
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 when 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
Fuse
AC--Alternating Current
DC--Direct Current
2) CENELEC DIRECTIVES
The instruments conform to CENELEC Low-voltage directive 2006/95/EC and
Electromagnetic compatibility directive 2004/108/EC

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3) PRODUCT DESCRIPTION
Note: Top of the line model is used as representative for illustration purposes. Please refer
to your respective model for function availability.
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.
1) 4 digits 9999 counts dual
displays
2) Push-buttons for special
functions & features
3) Selector to turn the Power On
or Off and Select a function
4) Input Jack for 10A (20A for
30sec) current function
5) Common (Ground reference)
Input Jack for all functions
6) Input Jack for all functions
EXCEPT current (A, mA, A)
functions
7) Input Jack for milli-amp and
micro-amp current functions

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Average sensing RMS calibrated
RMS (Root-Mean-Square) is the term used to describe the effective or equivalent DC value
of an AC signal. Most digital multimeters use average sensing RMS calibrated technique to
measure RMS values of AC signals. This technique is to obtain the average value by
rectifying and filtering the AC signal. The average value is then scaled upward (calibrated)
to read the RMS value of a sine wave. In measuring pure sinusoidal waveform, this
technique is fast, accurate and cost effective. In measuring non-sinusoidal waveforms,
however, significant errors can be introduced because of different scaling factors relating
average to RMS values.
True RMS
True RMS is a term which identifies a DMM that responds accurately to the 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. Harmonics 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.

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4) 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.
AutoCheckTM mode (Models 525s, 521s, 829s only)
This innovative AutoCheckTM feature automatically selects measurement function of DCV,
ACV or Resistance () based on the input via the test leads.
●With no input, the meter displays “Auto” when it is ready.
●With no voltage signal but a resistance below 60M is present, the meter displays the
resistance value. When below “Audible Threshold“ is present, the meter further gives a
continuity beep tone.
●When a signal above the threshold of 1.5V DC or 3V AC up to the rated 1000V is present,
the meter displays the voltage value in appropriate DC or AC, whichever larger in peak
magnitude.
Note:
*Range-Lock and Function-Lock Feature: When a measurement reading is being
displayed in AutoCheckTM mode, press the RANGE or SELECT button momentarily 1 time
can lock the range or function it was in. Press the button momentarily repeatedly to step
through the ranges or functions.

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*As Hazardous-Alert: When making resistance measurements in AutoCheckTM mode, an
unexpected display of voltage readings alerts you that the object under test is being
energized.
*Ghost-voltage Buster: Ghost-voltages are unwanted stray signals coupled from adjacent
hard signals, which confuse common multimeter voltage measurements. Our AutoCheckTM
mode provides low (ramp-up) input impedance (approx. 3kΩ at low voltage) to drain ghost
voltages leaving mainly hard signal values on meter readings. It is an invaluable feature for
precise indication of hard signals, such as distinguishing between hot and open wires (to
ground) in electrical installation applications.
WARNING:
AutoCheckTM mode input impedance increases abruptly from initial 3kΩ to a few hundred
kΩ’s on high voltage hard signals. “LoZ” displays on the LCD to remind the users of being
in such low impedance mode. Peak initial load current, while probing 1000VAC for example,
can be up to 471mA (1000V x 1.414 / 3kΩ), decreasing abruptly to approx. 3.1mA (1000V x
1.414 / 460kΩ) within a fraction of a second. Do not use AutoCheckTM mode on circuits that
could be damaged by such low input impedance. Instead, use rotary selector or high
input impedance voltage modes to minimize loading for such circuits.
dBm +Hz (Model 829s only), Hz +ACV, ACV +Hz functions
Press the SELECT button momentarily to select the subject functions in sequence. Last
selection will be saved as power up default for repeat measurement convenience.
Note: Hz Input sensitivity varies automatically with voltage (current function alike) range
selected. 1V range has the highest and the 1000V range has the lowest. Auto-ranging

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measurements normally set the most appropriate trigger level. You can also press the
RANGE button momentarily to select another trigger level (voltage range) manually. If the
Hz reading becomes unstable, select higher voltage range to avoid electrical noise. If the
reading shows zero, select lower voltage range.
Note: In dBm +Hz 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. Last selection will be saved as power up
default for repeat measurement convenience. Manual trigger level selection on Hz reading
is not available.
DC+ACV +ACV (Models 525s, 521s, 829s only), DCV, DCV +ACV functions
Press the SELECT button momentarily to select the subject functions in sequence. Last
selection will be saved as power up default for repeat measurement convenience.
Models 525s, 521s, 829s:
DCmV, DCmV +ACmV, DC+ACmV +ACmV, Logic-Level Hz & Duty%
Press the SELECT button momentarily to select the subject functions in sequence. Last
selection will be saved as power up default for repeat measurement convenience.
Models 827s, 822s, 821s:
DCmV, DCmV +ACmV, Logic-Level Hz & Duty%
Press the SELECT button momentarily to select the subject functions in sequence. Last
selection will be saved as power up default for repeat measurement convenience.

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ACmV +Hz, dBm +Hz (Model 829s only), Hz +ACmV functions
Press the SELECT button momentarily to select the subject functions in sequence. Last
selection will be saved as power up default for repeat measurement convenience.

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nS Conductance (Models 525s, 521s, 829s, 827s only),  Resistance, Continuity
functions
Press the SELECT button momentarily to select the subject functions in sequence for
models 525s, 521s, 829s and 827s. Last selection will be saved as power up default for
repeat measurement convenience. Direct rotary switch selection on  Resistance and
Continuity functions for models 822s and 821s.
Note:
Conductance is the inverse of Resistance, that is S=1/ or nS=1/G. It virtually extends
the Resistance measurements to the order of Giga-Ohms for leakage measurements.
Continuity function is convenient for checking wiring connections and operation of
switches. A continuous beep tone indicates a complete wire.
CAUTION
Using resistance and continuity function in a live circuit will produce false results and may
damage the instrument. In many cases the suspected component must be disconnected
from the circuit to obtain an accurate reading
Temperature functions (Models 525s, 521s, 829s, 827s only)
Press SELECT button momentarily to toggle between C and F readings. For Dual
Channel Temperature function models 829s & 525s, press T1-T2 (RANGE) button
momentarily can select T1, T2, T1 +T2 or T1-T2 +T2 readings. Last selection will be saved as
power up default for repeat measurement convenience.
Note: Be sure to insert the banana plug type-K temperature bead probe Bkp60 with correct
polarities. You can also use a plug adapter Bkb32 (Optional purchase) with banana
pins to type-K socket to adapt other standard type-K mini plug temperature probes.