Kusam-meco KM 255 User manual

PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
H
LoZ
C
MAX MIN
MW
kHz
F
mVA
8888
DIGITAL
MULTIMETER
MODEL - KM 255 / KM 257
we damage them or “burn them out”. If you incorrectly

Title Page
Safety................................................................. 01
Cenelec Directives.............................................04
General Specifications.......................................04
Electrical Specifications..................................... 07
International Electrical Symbols.........................13
Product Description............................................14
Operation............................................................18
Maintenance......................................................32
Test Certificate...................................................35
Warranty.............................................................36
TABLE OF CONTENTS
V : Category II 1000V, CAT III 600V and
CAT IV 300V AC & DC.
mAmA : Category III 500VAC and 300VDC.
A : Category III 600VAC and 300VDC.
1) SAFETY
Terms in this manual
WARNING : Identifies condition and actions that
could result in serious injury or even
death to the user.
CAUTION : identifies conditions and action that
could cause damage or malfunction in
the instrument.
This manual contains information and warning that
must be followed for operating the instrument safely
and maintaining the instrument in a safe operating
conditions. If the instrument is used in a manner
not specified by the manufactures, 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 IEC61010-1 2nd Ed.
EN61010-1 2nd Ed. UL61010-2nd Ed. and CAN/
CSA C22.2 No. 61010.1-1-0.92 to category II
1000V, CAT III 600V & CAT IV 300V AC & DC.
Terminals ( to COM) measurement category:
1

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
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 IV (CAT IV) is for
measurements performed at the source of the low-
voltage installation. Examples are electricity meters
and measurement on primary overcurrent
protection devices and ripple control units.
Per IEC61010-1 2nd Ed. (2001) Measurement
Category
2
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 voltage 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 mA/mA or A input jack. Only replace the
blown fuse with the proper rating as specified in
this manual.
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.
Warning
CAUTION
3

The instruments conforms to CENELEC Low-voltage
directive 2006/95/EC and Electromagnetic
compatibility directive 2004/108/EC
?Display : 3-5/6 digits 6,000 counts
?Update Rate : 5 per second nominal
?24 Segments Bar graph :40 per second max.
?Operating Temperature : 0°C to 40°C
?Relative Humidity : Maximum relative
humidity 80% for temperature up to 31°C
decreasing linearly to 50% relative humidity
at 40°C
?Altitude : Operating below 2000m
?Storage Temperature : -20°C~60°C,
<80% R.H. (With battery removed)
?Temperature Coefficient : Nominal 0.15 x
(specified accuracy) / °C @ (0°C~18°C or
28°C~ 40°C), or otherwise specified.
?Sensing :
KM255 : Average sensing
KM257 : True RMS sensing
2) CENELEC DIRECTIVES
3) GENERAL SPECIFICATION
4
?Pollution Degree : 2
?Safety : Double insulation per IEC61010-1 2nd Ed.
EN6100-1 2nd Ed., UL61010-1 2nd Ed. &
CAN / CSA C22.2 No. 61010.1-0.92 to
Category II 1000V, CAT III 600V and
CAT IV 300V AC & DC
?Transient Protection : 6.5kV (1.2/50ms surge)
?Terminals (to Com) Measurement Category :
V : Category II 1000V, CAT III 600V and
CAT IV 300V AC & DC.
mAmA : Category III 500VAC and 300VDC.
A : Category III 600VAC and 300VDC.
?E.M.C. : Meets EN61326 -1:2006 (En55022,
EN61000-3-2, EN61000-4-2,
EN61000-4-3, EN61000-4-4,
EN61000-4-5, EN61000-4-8,
EN61000-4-11)
In an RF field of 3V/m:
Capacitance function is not specified
Other function ranges:
Total Accuracy = Specified Accuracy+100 digits
Performance above 3V/m is not specified
?Overload Protection :
mA & mA : 0.63A/500Vac, IR 150kA @500Vac
A : 10A/600Vac IR 100kA@600Vac
V : 1050 Vrms, 1450 Vpeak
AutoCheckä, mV, Ohm & others : 600 Vrms
5

6
?Low Battery : Blow approx. 2.3V
?Power Supply: 1.5V AAA Size battery x 2
?Power Consumption (typical): 3.5mA
?APO Consumption (typical) : 10mA
?APO Timing : Idle for 34 minutes
?Dimension :161(L) x 80(W) x 50(H)mm
(With Holster)
?Weight : Approx. 340 gm (With Holster)
?Special Features : AutoCheckäV&W;
Auto-ranging MAX / MIN record ; Crest mode
(Peak Hold), Backlighted LCD ; Auto-ranging
Relative Zero mode; Display Hold; EF-
Detection (NCV); Interface capabilities with
PC computer; Input warning detection.
?Optional purchase accessories :
USB interface kit BRUA-20; Magnetic hanger
BMH-01; BKB32 banana plug to type-K
socket plug adaptor.
?Accessories :
Test lead pair : batteries installed ;
user’s manual; BKP 60 banana
plug type-K thermocouple.
7
True RMS model KM257 ACV & ACA accuracies
are specified from 5% to 100% of range or other-
wise specified . Maximun Crest Factor <3:1 at full
scale & 6:1 at half scale, and with frequency
components fall within the meter specified
frequency bandwidth for non-sinusoidal waveforms.
AC Voltage
4) Electrical Specification
Accuracy is given as ±(%of reading digits + number
of digits) or otherwise specified @ 23°C±5°C and
less than 75% R.H.
Range
50Hz ~ 400Hz
60.00 mV
600.0 mV
6.000 V
60.00 V
600.0 V
1000 V
Resolution Accuracy
±(1.0%rdg + 5dgts)
CMRR : >60dB @ DC to 60Hz, Rs= 1kW
Input Impedance : 10MW, 50 pF nominal
DC Voltage
NMRR : >60dB @ DC to 50Hz / 60Hz
CMRR : >100dB @ DC, 50Hz / 60Hz; Rs= 1kW
Input Impedance : 10MW, 50 pF nominal
Range
60.00 mV
600.0 mV
6.000 V
60.00 V
600.0 V
1000 V
Resolution Accuracy
±(0.2%rdg + 3dgts)
10 mV
100 mV
1 mV
10 mV
100 mV
1 V
10 mV
100 mV
1 mV
10 mV
100 mV
1 V

AutoCheckä_ACV
AutoCheckäLo-Z ACV Thershold : >1V nominal
AutoCheckäLo-Z ACV input Impedance:
Initially approx. 2.5kW, 120pF nominal;
Impedance increases abruptly within a fraction of a
second as display voltage is above 50V(typical).
Ended up impedance vs display voltages typically are:
15kW@100V
100kW@300V
250kW@600V
375kW@1000V
Range
50Hz / 60Hz
1.000V~1000V
AutoCheckä_DCV
TM
AutoCheck Lo-Z DCV Threshold :
>+1.0VDC & <-1.0VDC nominal.
TM
AutoCheck Lo-Z DCV Input Impedance :
Initially approx. 2.5kW, 120pF nominal;
Impedance increases abruptly within a fraction of a
second as display voltage is above 50V(typical).
Ended up impedances vs display voltages typically are :
15kW@ 100V
100kW@ 300V
250kW@ 600V
375kW@ 1000V
8
Accuracy
±(1.4%rdg+5dgts)
Resolution
1mV~1V
Range
50Hz / 60Hz
1.000V~1000V
Accuracy
±(1.3%rdg+3dgts)
Resolution
1mV~1V
Resistance
Open Circuit Voltage : 0.45VDC typical.
Range
600.0 W
6.000 KW
60.00 KW
600.0 KW
6.000 MW
600.00 MW
Resolution Accuracy
±(0.5%rdg + 4dgts)
±(0.7%rdg + 4dgts)
±(1.2%rdg + 4dgts)
CREST Mode :
Accuracy : Specified accuracy plus 150 digits for changes
> 5ms in duration.
RECORD Mode :
Accuracy : Specified accuracy plus 100 digits for change
>100ms in duration.
TM
Autocheck Ohm :
1)
Range Accuracy
00.00W~ 60.00MW
±(1.2%rdg+10dgts)
Open Circuit Voltage : 0.45VDC typical.
1) TM
AutoCheck Ohm Threshold : < 10.00MWnominal
Audible Continuity Tester:
AudibleThreshold Response time
32ms
Between 10Wand 80W
9
100 mW
1 W
10 W
100 W
1 kW
10 kW
Resolution
10mW~10kW

11
AC Current
Range Resolution Accuracy
600.0 mA
6000 mA
60.00 mA
600.0 mA
6.000 mA
1)
8.00 A
±(1.0%rdg + 3dgts)
Burden Voltage :
0.10mV/mA (600.0mA & 6000mA) ranges.
1.7mV/mA (60.00mA & 600.0mA) ranges
1)
0.03V/A (6.000mA & 8.00A ) ranges.
1) 8A Continuous, > 8A to 15A for 30 Sec. Max. with
5 minutes cool down interval.
50Hz ~ 400Hz
10Hz - 50kHz
10Hz - 10kHz
10Hz - 10kHz
10Hz - 10kHz
10Hz - 10kHz
10Hz - 10kHz
10Hz - 50 kHz
10Hz - 1kHz
10Hz - 1kHz
45Hz - 1kHz
Sensitivity
(sine RMS)
400 mA
400 V
40 mA
40 mA
0.4 V
40 V
4 mA
6 A
1 A
4 V
Function
6000 mA
600 mA
600 mA
600 V
1000 V
60 mA
6 V
60 V
6 A
10 A
Hz (Line ) @ ACV, DCV, Current & AutoCheckä
Range
Accuracy : 0.03% + 3d
100 nA
1 mA
10 mA
100 mA
1 mA
10 mA
10
Accuracies with film capacitor or better
Capacitance
Range
60.00 nF
600.0 nF
6.000 mF
60.00 mF
600.0 mF
3000 mF
Resolution Accuracy
±(2.0%rdg + 5dgts)
±(1.5%rdg + 5dgts)
±(2.0%rdg + 5dgts)
Diode Tester
Range Accuracy
Test Current : 0.56mA typical.
Open Circuit Voltage : <1.8VDC typically.
±(1.0%rdg + 3dgts)
1.000 V
DC Current
Range
600.0 mA
6000 mA
60.00 mA
600.0 mA
6.000 mA
1)
8.00 A
Resolution Accuracy
±(0.5%rdg + 3dgts)
Burden Voltage :
0.10mV/mA (600.0mA & 6000mA) ranges.
1.7mV/mA (60.00mA & 600.0mA) ranges
1)
0.03V/A (6.000mA & 8.00A ) ranges.
1) 8A Continuous, > 8A to 15A for 30 Sec. Max. with
5 minutes cool down interval.
10 pF
100 pF
1 nF
10 nF
100 nF
1 mF
Resolution
100 mV
100 nA
1 mA
10 mA
100 mA
1 mA
10 mA

12
Bar-Graph
Indication
Typical Voltage
Temperature
Range Accuracy
-50°C ~ 1000°C
-58°F ~ 1832°F ±(0.3%rdg + 6dgts)
±(0.3%rdg + 3dgts)
K Type Thermocouple range & accuracy not included.
Supplied Thermocouple suitable for measurement
upto 250°C.
Logic Level Hz (mV Function)
Range Sensitivity (square wave)
5.00Hz ~ 500.0kHz 3 Vpeak
Accuracy : 0.03% + 2d.
5.00Hz ~ 1.000MHz 5 Vpeak
Non-Contact EF-Dection :
440V (tolerance:250V~1000V)
220V (tolerance:124V~330V)
110V (tolerance:59V~165V)
55V (tolerance:23V~83V)
20V (tolerance:10V~36V)
Indication : Bar-graph segments & audible beep tones
proportional to the field strength.
Detection Frequency : 50 / 60Hz
Detection Antenna : Top-right end of the meter
Probe-Contact EF-Detection: For more precise indication
of live wires, such as distinguishing between live &
ground connections, use the Red (+) test probe for
direct contact measurements.
13
~
5) 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

15
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.
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, pluse trains, spikes, as well as
distorted waveforms with the presence of
harmonics. Harmonics may cause:
14
6) PRODUCT DESCRIPTION
Note: Top of the line model is used as representative
for illustration purposes. Please refer to your
respective model for function availability.
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
H
LoZ
C
MAX MIN
MW
kHz
F
mVA
8888
1
2
3
4
5
6
7
1. 3-5/6 digits
6000 counts
LCD display
2. Push-buttons
for special
functions &
features
3. Selector to
turn the Power
On or Off &
Select a function
4. Input Jack for
milli-amp and
micro-amp
current functions
5. Input Jack for all functions EXCEPT current
(mA, mA, A) functions
6. Common (Ground reference) Input Jack for all
functions.
7. Input Jack for 8A (15A for 30sec) current
function

16
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
1) Overheated transformers, generators and
motors to burn out faster than normal
2) Circuit breakers to trip prematurely
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.
Crest Factor
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
means a good ability to reject the effect of AC
noise in DC measurements.
NMRR (Normal Mode Rejection Ratio)
17
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
measurements. This series has a CMRR
specifications of >60dB at DC to 60Hz in ACV
function; and >120dB at DC, 50 and 60 Hz in DCV
function. If neither NMRR nor CMRR specification
is specified, a DMM’s performance will be
uncertain.
CMRR (Common Mode Rejection Ratio)

18
B e f o r e a n d a f t e r h a z a r d o u s v o l t a g e
measurements, test the voltage function on a
known source such as line voltage to determine
proper meter functioning.
7) OPERATION
CAUTION
Auto Check V - W
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
LoZ
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
LoZ
V
4520
LoZ
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
LoZ
V
3808
LoZ
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
LoZ
k
3028
LoZ
W
Auto
Check
(Loz)
19
?When a signal above the voltage threshold of 1V
DC or AC up to the rated 1000V is present, the
meter displays the voltage value in appropriate
DC or AC, whichever larger in peak magnitude.
*Range-Lock and Function-Lock Feature:
When a measurement reading is being displayed in
AutoCheckämode, press the RANGE or SELECT
button momentarily 1 time can lock the range or
functions it was in. Press the button momentarily
repeatedly to step through the ranges or functions.
AutoCheckämode
This innovative AutoCheckäfeature automatically
selects measurement function of DCA, ACV or
Resistance (W) 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
10MW(nominal) is present, the meter displays
the resistance value. When the resistance is
below “Audible Threshold”, the meter further
gives a continuity beep tone.
Note:

20
*As Hazardous-Alter : When making resistance
measurement in AutoCheckämode, an unexpected
display of voltage readings alters you that the object
under test is being energized.
*Ghost-voltage Buster : Ghost-voltages are
unwanted stray signals coupled form adjacent hard
signals, which confuse common multimeter
voltages measurements. Our AutoChecksämode
provides low(ramp-up) input impedance (approx.
2.5kWat 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.
AutoChecksämode input impedance increases
abruptly from initial 2.5kWto a few hundred kW’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 566mA
(1000V x 1.414 / 2.5kW),decreasing abruptly to
approx. 3.8mA (1000V x 1.414 / 375kW)within a
fraction of a second. Do not use AutoCheckä
mode on circuits that could be damaged by such
low input impedance. Instead, use rotary selector
v or v high input impedance voltage modes to
minimize loading for such circuits.
WARNING:
Press the Hz push-buttion for one second or more
to activate or to exit Hz.
DCV, ACV & Line Frequency functions
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
V
4520
V
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
V
3808
V
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
Hz
6028
V
1S
DCV ACV
Hz
21

22
*Input sensitivity varies automatically with function
range selected before activating the Hz function.
6V function range has the highest and the 1000V
range has the lowest. It is recommended to first
measure the signal voltage (or current ) level then
activate the Hz function in that voltage (or current)
range to automatically set the most appropriate
trigger level. You can also press the RANGE button
momentarily to select another trigger level
manually. If the Hz reading becomes unstable,
select lower sensitivity to avoid electrical noise. If
the reading shows zero, select higher sensitivity.
*Number of Bar-graph pointer is used to indicate
input range (sensitivity) selected. 1 / 2 / 3 / 4
pointers indicate 6 / 60 / 600 / 1000V, 6 / 10 / - / -A,
60 / 600 / - / -mA or 600 / 6000 / - / -mA is selected
in corresponding V, A mA or mA function
respectively. (“-” means range not available)
Note:
* The Hz of mV function is designed specially for
logic level (3V or 5V family) frequency
measurement.
23
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.
WResistance, Continuity , Capacitance,
Diode test functions
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
W
5980
W
W
W
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
W
00 1 5
W
SELECT
1
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
3280
W
SELECT
1
AUTO
mF
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
0608
W
SELECT
1
V
Diode
FORWARD BIAS
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
OL
W
V
Diode
REVERSE BIAS

25
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.
DCmV, ACmV, Temperature °C & °F functions
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
mV
4520
DCmV
Temp
mV
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
mV
3808
ACmV
SELECT
1S
K-temp
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
086C
SELECT
1
K-temp
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
87F
SELECT
1
24
Normal forward voltage drop (forward biased) for a
good silicon diode is between 0.400V to 0.900V. A
reading higher than that indicates a leaky diode
(defetive). A zero reading indicates a shorted
diode (defetive). An OL indicates an open
diode(defective). Reverse the test leads
connections (reverse biased) across the diode. The
digital display shows OL if the diode is good. Any
other readings indicate the diode is resistive or
shorted(defective).
CAUTION
Discharge capacitors before making any
measurement. Large value capacitors should be
discharged through an appropriate resistance load.
Using resistance and continuity function in a live
circuit will produce false results and may damage
the instrument. In may cases the suspected
component must be disconnected from the circuit to
obtain an accurate reading.
CAUTION
Continuity function is convenient for checking
wiring connections and operation of switches. A
continuous beep tone indicates a complete wire.

26
Note : Be sure to insert the banana plug
K-type temperature bead probe Bkp60 with
correct + - polarities. You can also use a plug
adapter Bkb32 (Optional purchase) with banana
pins to K-type socket to adapt other standard
K type mini plug temperature probes.
Press SELECT button momentarily to toggle
between DC and AC. Last selection will be
saved as power up default for repeat
measurement convenience.
mA, mA, and A Current functions
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
m
2785
W
A
mA
mA
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
m
5 09
W
A
mA
mA
SELECT
1
27
*Note: When measuring a 3-phase system, special
attention should be taken to the phase-to-phase
voltage which is significantly higher than the
phase-to-earth voltage. To avoid exceeding the
voltage rating of the protection fuses(s)
accidentally, always consider the phase-to-phase
voltage as the working voltage for the protection
fuse(s).
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
m
2 08
W
A
mA
mA
5
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
AUTO
5 2
W
A
A
A
0

28
At Volt or Current funcion, press the EF button for
one second or more and release to toggle to
EF-Detection feature. The meter displays “E.F”
when it is ready. Signal strength is indicated as a
series of bar-graph segments on the display plus
variable beep tones.
Electric Field EF-Detection
EF (NCV)
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
E F
EF
1S
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
E F
PC-Comm
MAX 0.6A
HBC FUSED
MAX 8A
HBC FUSED
ACOM
JACK
300V CAT IV
600V CAT III
1kV CAT II
!
Temp
W
V
JACK
mA
mA
mA
mA
mV A
W
V
V
Temp
Auto
Check
(Loz)
OFF
REC
CREST
SELECT RANGE REL HOLD
Hz EF
Live Ground
For more precise indication of live wires, such as
distinguishing between live & ground connections,
use the Red (+) test probe for direct contact
measurements.
?Non-Contact EF-Detection :
An antenna is located along the top-right end of the
mater, which detects electric field surrounds current
carrying conductors. It is ideal for tracing live wiring
connections, locating wiring breakage and to
distinguish between live or earth connections.
?Probe-Contact EF-Detection :
PC computer interface capabilities
The instrument equips with an optical isolated
interface port at the meter back for data
communication. Optional purchase PC interface kit
BRUA20X is required to connect the meter to the
PC computer RS232 or USB ports.
MAX/MIN at Fast 20/s measurement mode
Press REC button momentarily to activate MAX/
MIN recording mode. The LCD “MAX MIN” turn on,
and the reading update rate will be increased to
20/second. The meter beeps when new MAX
(maximum) or MIN (minimum) reading is updated.
Press the button momentarily to read the MAX and
MIN readings in sequence. Press the button for 1
second or more to exit MAX/MIN recording mode.
Auto-ranging remains, and Auto-Power-Off is
disabled automatically in this mode.
29

Press CREST button momentarily to activate
CREST (instantaneous Peak-Hold) mode to capture
voltage or current signal duration as short as 5ms.
The LCD “C” & “MAX” turn on. The meter beeps
when new MAX(maximum) or MIN(minium) reading
is updated. Press the button momentarily to read
the MAX and MIN readings in sequence. Press the
button for 1 second or mode to exit CREST capture
mode. Auto-ranging and Auto-Power-Off are
disabled automatically in this mode.
5ms CREST capture mode
Backlighted LCD display
Press the SELECT button for 1 second or more to
toggle the LCD backlight. The backlight will also be
turned off automatically after 32 second to extend
battery life.
Hold
The hold feature freezes the display for later vies.
Press the HOLD button momentarily to toggle the
hold feature.
Relative Zero ( ) mode
Relative zero allows the user to offset the meter
consecutive measurements with the displaying
reading as the reference value. Practically all
displaying readings can be set as relative reference
value including MAX/MIN feature readings. Press
the REL button momentarily to toggle relative zero
mode.
30
The Auto-Power-Off (APO) mode turns the meter
off automatically to extend battery life after approx.
34 minutes of no rotary switch or push button
operations. To wake up the meter from APO, press
the SELECT, CREST or REC button momentarily
or turn the rotary switch OFF and then back on.
Always turn the rotary switch to the OFF position
when the meter is not in use and then back on.
Press the RANGE button momentarily to select
manual-ranging, and the meter will remain in the
range it was in, the LCD turns off. Press
the button momentarily again to step through the
ranges. Press and hold the button for 1 second or
more to resume auto-ranging.
Note : Manual ranging feature is not available in
Hz and functions.
AUTO
Manual or Auto- ranging
Set Beeper Off
Press the RANGE button while turning the meter
on to temporarily disable the Beeper feature. Turn
the rotary switch OFF and then back on to resume.
Beep-JackäInput Warning
The meter beeps as well as display “InEr” to warn
the user against possible damage to the meter due
to improper connections to the mA, mA or A input
jacks when other function (like voltage function) is
selected.
Auto-Power-Off (APO)
31

If the instrument fails to operate, check battery,
fuses, leads, etc., and replace as necessary.
Double check operating procedure as described in
this user’s manual.
Trouble Shooting
If the instrument voltage-resistance input terminal
has subjected to high voltage transient (caused by
lightning or switching surge to the system) by
accident or abnormal conditions of operation, the
series fusible resistors will be blown off (become
high impedance) like fuses to protect the user and
in the instrument. Most measuring functions
through this terminal will then be open circuit. The
series fusible resistors and the spark gaps should
then be replaced by qualified technician. Refer to
t h e WA R R A N T Y s e c t i o n f o r o b t a i n i n g
warranty or repairing service.
33
To avoid electrical shock, disconnect the meter
from any circuit, remove the test leads from the
input jacks and turn OFF the meter before opening
the case. Do not operate with open case. Install
only the same type of fuse or equivalent.
Cleaning and Storage
Periodically wipe the case with a damp cloth and
mild detergent; do not use abrasives or solvents. If
the meter is not to be used for periods of longer
than 60 days, remove the battery and store it
separately.
Press the SELECT button while turning the meter
on to temporarily disable the Auto-Power-Off (APO)
feature. Turn the rotary switch OFF and then back
on to resume.
Disabling Auto-Power-Off
MAINTENANCE
WARNING
32

Battery use : 1.5V AAA Size battery x 2
Fuses use : Fuse (FS1) for mAmA current input
: 0.63A/500Vac, IR 150kA. F fuse;
Fuse(FS2) for A current input:
10A/600Vac, IR 100kA, F fuse
Battery and Fuse replacement :
Loosen the screw from the access cover of the
case bottom. Lift the access cover. Replace the
batteries or fuse. Re-fasten the screw.
Battery and Fuse replacement
34
This Test Certificate warrantees that
the product has been inspected and
tested in accordance with the published
specifications.
The instrument has been calibrated by
using equipment which has already
been calibrated to standards traceable
to national standards.
QC
PASS
KUSAM-MECO
TEST CERTIFICATE
DIGITAL MULTIMETER
MODEL NO. __________
KM 255 / 257
SERIAL NO. ___________
MUMBAI
DATE: ___________
ISO 9001
REGISTERED
35

All transaction are subject to Mumbai Jurisdiction.
G 17,Bharat Industrial Estate, T. J. Road,
Sewree (W), Mumbai - 400 015. INDIA.
Sales Direct : [phone]
Tel. : [phone].
Fax : [phone]
Email : [email protected]
Website : www.kusamelectrical.com,
www.kusam-meco.co.in
3736
warranty period is Two years (24 months) and