Extech Instruments MultiScope 381270 User manual

Owner's Manual
Model 381270 & 381275 MultiScopeTM
CAUTION: Read, understand and follow all Safety Rules and Operating Instructions in
this manual before using this product.

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TABLE OF CONTENTS Page
Safety Instructions 3
Safety Symbols 4
Specifications 5
Meter Description 7
Controls 7
Display Symbols 8
Graphical Display Description 9
Operating Instructions 10
AC Voltage Measurements 10
DC Voltage Measurements 10
mV Voltage Measurements 11
Resistance, Conductance and Continuity 11
Capacitance and Diode Measurements 11
mA and uA Current Measurements 11
Current Measurements 12
RPM Measurements 12
Signal Out 12
AUX 12
Install 12
Frequency Measurements 13
Trigger Level 13
Duty Ratio 13
Pulsewidth 13
Period 13
Min Max 13
Memory Storage 14
Auto/Manual Range 14
Relative 14
Peak-Hold 14
dB 14
Time (graphical) 14
Trigger (graphical) 15
Glitch 15
Software 16
Tilt Stand 17
Battery Replacement 17
Fuse Repacement 17
Warranty 18

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WARNING: USE EXTREME CAUTION IN THE USE OF THIS DEVICE. Improper
use of this device can result in injury or death. Follow all safeguards suggested in this
manual. In addition to the normal safety precautions used in working with electrical
circuits. DO NOT service this device, if you are not qualified to do so.
SAFETY INSTRUCTIONS
This meter has been designed to be safe in use, but the operator must use caution in
its operation. The rules listed below should be carefully followed for safe operation.
•Avoid Working Alone.
•Do not use Non-Rechargeable Batteries (Alkaline, Carbon Zinc etc.) together with
the AC power Adapter.
•Do not turn the Rotary switch to HI-Z/ range while the Test Leads are connected to
a High Voltage
•When measuring resistance (OHMS) be sure the circuit is non-powered. Ohms can
not be measured if there is voltage in the circuit being measured.
•When using the inductive pick up lead, be sure you keep the inductive clamp away
from adjoining high tension spark plugs leads to prevent the clamp from picking up
signals from those leads.
•Use a current clamp to measure circuits exceeding 20A.
•When measuring current, turn the power off before connecting the meter to the
circuit.
•Select the proper function and range for your measurement.
•Never connect more than one set of test leads to the meter.
•Disconnect the live test lead before disconnecting the common test lead.
•Choose the proper range and function for the measurement.
•Do not try voltage or current measurements that may exceed the ratings marked on
the function/range switch or terminal.
•Avoid Electrical Shock. Do not touch the test leads tips or the circuit being tested.
•Never operate the meter unless the back cover and the battery/fuse door are in
place and fastened securely

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SAFETY SYMBOLS
This symbol adjacent to another symbol, terminal or operating
device indicates that the operator must refer to an explanation in
the Operating Instructions to avoid personal injury or damage to
the meter.
This WARNING symbol indicates a potentially hazardous
situation, which if not avoided, could result in death or serious
injury.
This CAUTION symbol indicates a potentially hazardous
situation, which if not avoided, may result in minor or moderate
injury or damage to the product or other property.
This symbol advises the user that the terminal(s) so marked must
not be connected to a circuit point at which the voltage, with
respect to earth ground, exceeds (in this case) 500 VAC or VDC.
This symbol adjacent to one or more terminals identifies them as
being associated with ranges that may, in normal use, be
subjected to particularly hazardous voltages. For maximum
safety, the test leads should not be handled when these terminals
are energized.
WARNING
CAUTION
MAX

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SPECIFICATIONS
Display 128x64 pixel graphic LCD (view area: 2.8x1.5”, 71.7x39mm)
Measurement rate Digital: 4 times/sec; Bar-Graph: 7 times/sec.
Auto Power Off After 30 minutes of inactivity
Overrange indication “OVER”
Display rate Digital display; 4/second Bargraph; 7/second
Input resistance 10MΩ, >2GΩon mV range
Power 6 size AA cells, 6 size AA Nicad batteries, 2 Ni-Cad Battery
Pack or AC adaptor
Operating time: Alkaline (6hrs approx.), Ni-Cad (8hrs
approx.) Ni-Cad Charging time (3hrs approx.)
Temperature Operating: 32OF to 104OF(0OC to 40OC), Storage (Ni-Cad
batteries removed): -4OF to 140OF (-20OC to 60OC),
Charging: 32OF to 113OF(0OC to 45OC)
RS232 Interface Baud Rate: 9600, Data bit: 8 bit, Stop bit: 1 bit, Parity: none
Min/Max/Avg. Records minimum, average and maximum value
Hold Captures displayed reading
Storage 15 pages (text or graphic)
Dimensions/weight 4.2x8.3x2.2” (107x210x55mm) / 1.77lbs. (800gm)
Digital Storage Oscilloscope
Display Number of Channels One
Bandwidth DC to 100kHz
Volt / Division (4 divisions) 150mV to 400V
Sample Rate 1.0MSPS
Horizontal Number of Channels One
Second / Division (9 divisions) 10usec. to 1 second
Record length 25 div
Glitch Capture 500nsec. (minimum)
Multimeter Range Resolution Accuracy
400mV 0.1mV
4V 0.001V
40V 0.01V
400V 0.1V
DC Voltage
1000V 1V
±(0.5%rdg + 10dgt)
400mV 0.1mV
4V 0.001V
40V 0.01V
400V 0.1V
AC Voltage True
RMS
700V 1V
±(0.75%rdg + 10dgt) RMS
50Hz to 1kHz
400uA 0.001mA
400mA 0.1mA
DC Current
20A 0.01A
±(1.0%rdg + 10dgt)
400uA 1µA
400mA 0.1mA
AC Current
20A 0.01A
±(1.2%rdg + 10dgt) RMS
50Hz to 1kHz

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Multimeter Range Resolution Accuracy
400Ω0.1Ω
4kΩ0.001kΩ
40kΩ0.01kΩ
400kΩ0.1kΩ
4MΩ0.001MΩ
±(1.0%rdg + 5dgt)
Resistance
40Mohms 10kohms ±(3.0%rdg + 5dgt)
Conductance 0025 to 0999nS 1nS ±(3.0%rdg + 5dgt)
4nF 0.001nF
40nF 0.01nF
400nF 0.1nF
4µF 0.001µF
Capacitance
40µF 0.01uF
±(3.0%rdg + 5dgt)
1,000Hz 1HzFrequency
100kHz 1kHz
±(1.0%rdg + 5dgt)
Diode Test 1mV ±(2.0%rdg + 5dgt)
dB -80 to +80dB Reference values: 2, 4, 8, 16, 50, 75, 93,
110, 125, 135, 150, 300, 600, 900, 1000Ω
RPM 12000rpm 10rpm ±(3.0%rdg + 10rpm)
4000usec 1usecPeriod/Pulse
Width 1000msec 1msec
±(3.0%rdg + 5dgt)
Duty Cycle 1 to 100% 0.1% ±(3.0%rdg + 5dgt)
10Hz – 100Hz 1Hz
100Hz - 1000Hz 10Hz
Signal Out
1kHz – 20kHz 1kHz
±(1.2% + 5 digits)
OVERLOAD PROTECTION
Input Overload Protection
Function Maximum Input
V DC, V AC 1000V DC or AC peak, less than 10 sec
mV AC, mV DC 250V DC or AC peak, less than 10 sec
mA DC/AC 400mA DC / AC, Fused: 0.4A/250V ceramic fast blow
20A DC/AC 20A DC or AC, less than 30 sec with a 15 min cool
down period, Fused: 20A/250V ceramic fast blow
RPM 250V Dc or AC rms, less than 10 sec
Period/Pulse Width 250V DC or AC rms, less than 10 sec
Duty Cycle 250V DC or AC rms , less than 10 sec
Capacitance None
Diode None
WARNING: To avoid electric shock and damage to the meter, do not test
any diode or capacitor that has voltage on it

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BASIC METER FUNCTIONS
1. RS 232 Computer lnterface Socket
2. AC Adapter Input Socket
3 LCD Screen display
4. Soft keys and labels
5. Buttons (Select mode of operation)
6. Rotary Switch (Select function).
7. Input jacks
CONTROLS
Soft function keys F1, F2,
F3, F4
These four keys perform
the function indicated on
the LCD display. The
function will change
depending on the position
of the rotary switch and the
mode of operation.
RST: Power reset key to re-activate power if the auto-shutoff is in effect after
30 minutes of inactivity.
MODE: Toggle between the multimeter text mode and the oscilloscope
graphics mode. The graphics mode functions in the V, A, and mV
modes.
HOLD: “Freezes” the reading on the display. Press “Hold” again to resume
normal operation. The hold symbol “H” will appear on the display when
Hold is selected.
HELP: Displays three screens (safety, connections, procedure) for the
function selected on the rotary switch. The F4 key steps through the
pages. Press “HELP” to exit.
HZ: Selects the Frequency mode in V functions.
MIN/MAX: Selects the MIN, MAX, Average display.
STORAGE: Store and recall measurement data or graphical display.
RANGE: Holds and selects a measurement range. Hold the key for 2 seconds
to return to auto-range.

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BASIC DISPLAYS
Multimeter Mode
Oscilloscope Mode
DISPLAY SYMBOLS
A Ampere
AC Alternating current
AUTO auto ranging
Ave average
BEEPER Button beeper
CALL Recall stored data
CLEAR Remove stored data
dB Decibel
DC Direct current
div division (graph mode)
DUTY Duty cycle
F Farads (capacitance)
Glitc Glitch Waveform
Hi-A High Current
Hi-Z High Impedance
Hz Hertz (frequency)
Max maximum
Min minimum
nS Nano Siemens (Conductance)
oC Degrees Centigrade
oF Degrees Fahrenheit
OUT Signal out
PAUSE Pause in “MIN/MAX” mode
P-H Peak Hold
Psi,kPa Pressure
RANGE manual ranging
REL Relative
RESET Reset
RMS True RMS
RPM revolution per minute
RS232 RS 232 Interface is on
RUN Record in “MIN/MAX” mode
Singl Single Waveform
SLEEP Auto shut-off
TEST Self Test (Install function)
Time Time change (graph mode)
TRIG Frequency Trigger
V Volts
Ωohms (resistance)
%RH Relative Humidty
2 cyl 2 cycle engine
4 cyl 4 cycle engine
Buzzer, Continuity
cursor (left or right)
%& cursor (up or down)
Low Battery Indication
Overrange on A & V ranges.
AC adaptor is connected

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GRAPHICAL DISPLAY DESCRIPTION
1. The graphical mode is entered when the “MODE” key is pressed when the function
switch is in the ACV, DCV, mV, ACA or DCA position
2. The amplitude (vertical) and time (horizontal) divisions are selected automatically
when in the autoranging mode. The time division will vary to display the best wave
pattern in the autoranging mode or can be set manually using the “F1” and arrow
keys. The volts/division is determined by the range selected and cannot be varied.
SOFT KEYS AND SUB-MENUS
Function keys F1, F2, F3, and F4 are located directly below the LCD display and
perform multiple operation as indicated on the LCD and determined by the function
selected by the rotary switch. Some functions will produce a sub-menu on the display
for further selection. Operation of the menus and sub-menus is described in the
appropriate operation paragraph.

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OPERATING INSTRUCTIONS
WARNING: Risk of Electrocution. High-voltage circuits, both AC and DC, are very
dangerous and should be measured with great care.
1. ALWAYS set the power switch to the OFF position when the meter is not in use.
2. If “OVER” appears in the display during a measurement in the manual range mode,
the value you are measuring exceeds the range you have selected. Change to a
higher range.
AUTORANGE / MANUAL RANGE SELECTION
The meter will turn on in the autoranging mode. For most applications this is the
easiest and most accurate method of measurement. For measurements that require
the range to be held:
1. Press the “RANGE” key. The display will change from “AUTO” to “RANGE” (manual
range) with the full scale value displayed.
2. Each time the “RANGE” key is pressed, the next available range will be set.
3. To return to “AUTO” range, hold the “RANGE” key for 4 seconds.
DATA HOLD
The meter will freeze the reading in the display when the HOLD key is pressed. “H”
will apear in the display when HOLD is activated. Press HOLD again to resume
normal operation.
AUTO POWER OFF
The meter will automatically shut off after 30 minutes if a push button is not pressed or
the rotary switch is not moved. The symbol in the upper left of the display indicates the
time left to shut off.
AC VOLTAGE MEASUREMENT
1. Turn the rotary switch to the ACV position.
2. Press the HELP key and then the F4 key to display
procedures, cautions and connection diagrams
regarding ACV measurements.
3. Press the HELP key again to exit the HELP screens.
DC VOLTAGE MEASUREMENT
1. Turn the rotary switch to the DCV position.
2. Press the HELP key and then the F4 key to display
procedures, cautions and connection diagrams
regarding DCV measurements.
3. Press the HELP key again to exit the HELP screens