Brymen BM821 User manual

USER'S MANUAL
BM821, BM822, BM827, BM829
BM521, BM525

1
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 IEC61 1 -1 2nd Ed.,
EN61 1 -1 2nd Ed., UL61 1 -1 2nd Ed. and CAN/CSA C22.2 No. 61 1 .1- .92 to Category
IV 1 Volts AC & DC.
BM821, BM822, BM827 & BM829 Terminals (to COM) measurement category:
V : Category IV 1 Volts AC & DC
mAµA : Category IV 6 Volts AC and 3 Volts DC
A : Category IV 6 Volts AC and 3 Volts DC
BM521 & BM525 Terminals (to COM) measurement category:
V / mAµA / A : Category IV 1 Volts AC & DC
Per IEC61010-1 2nd Ed. (2001) Measurement Cate ory
Measurement Cate ory 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 Cate ory 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 Cate ory 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.

2
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 6 VDC or 3 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 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 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 2 6/95/EC and
Electromagnetic compatibility directive 2 4/1 8/EC

3
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.
Analo bar- raph
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 1 A (2 A for
3 sec) current function
5) Common (Ground reference)
Input Jack for all functions
6) Input Jack for all functions
EXCEPT current (µA, mA, A)
functions
7) Input Jack for milli-amp and
micro-amp current functions

4
Avera e sensin 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 nown
source such as line voltage to determine proper meter functioning.
AutoCheck
TM
mode (525, 521, 829 only)
This innovative AutoCheck
TM
feature automatically selects measurement function of DCV,
ACV or Resistance (Ω) 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 6 MΩ 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 1 V 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 AutoChec
TM
mode, press the RANGE or SELECT button momentarily 1 time
can loc the range or function it was in. Press the button momentarily repeatedly to step
through the ranges or functions.

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*As azardous-Alert: When ma ing resistance measurements in AutoChec
TM
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 AutoChec
TM
mode provides low (ramp-up) input impedance (approx. 3 Ω 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:
AutoChec
TM
mode input impedance increases abruptly from initial 3 Ω to a few hundred
Ω’s on high voltage hard signals. “LoZ” displays on the LCD to remind the users of being in
such low impedance mode. Pea initial load current, while probing 1000VAC for example,
can be up to 471mA (1000V x 1.414 / 3 Ω), decreasing abruptly to approx. 3.1mA (1000V x
1.414 / 460 Ω) within a fraction of a second. Do not use AutoChec
TM
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
(829 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 1 V 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-Ω
ΩΩ
Ω (RANGE) button momentary to
select different reference impedance of 4, 8, 16, 32, 5 , 75, 93, 11 , 125, 135, 15 , 2 ,
25 , 3 , 5 , 6 , 8 , 9 , 1 , up to 12 Ω
ΩΩ
Ω. 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
(525, 521, 829 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.
525, 521, 829:
DCmV, DCmV
+ACmV
, DC+ACmV
+ACmV
, Lo ic-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.
827, 822, 821:
DCmV, DCmV
+ACmV
, Lo ic-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
(829 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.

9
nS Conductance (525, 521, 829, 827 only), Ω
ΩΩ
Ω Resistance, Continuity functions
Press the SELECT button momentarily to select the subject functions in sequence for
models 525, 521, 829 and 827. Last selection will be saved as power up default for repeat
measurement convenience. Direct rotary switch selection on Ω
ΩΩ
Ω Resistance and
Continuity functions for models 822 and 821.
Note:
Conductance is the inverse of Resistance, that is S=1/Ω or nS=1/GΩ. 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 (525, 521, 829, 827 only)
Press SELECT button momentarily to toggle between °C and °F readings. For Dual Channel
Temperature function models 829 & 525, 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 Bkp6 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.