Conrad VC940 Operating Manual
Model VC940: OPERATING MANUAL
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Table of Contents
Chapter Title Page
1 Before You Start
Overview
Unpacking Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
2 Getting Acquainted
Turning the Meter On
Battery Considerations
Automatic Power Off
Automatic Backlight Off
Low Battery Indication
The Meter Structure
Rotary Switch
Functional Buttons
The Meter Functions Vs Displays
Selecting the Range
Understanding the Display
Analogue Bar Graph
Using MAX MIN
3 Making Measurements
A. Measuring Voltages
B. Measuring Currents
C. Measuring Resistance
D. Testing for Continuity
E. Testing Diodes
F. Measuring Capacitance
G. Measuring Frequency / Duty Cycle
H. Measuring Temperature
I. 4~20mA loop current as % readout
J. Power Measurement
4 Using Stores, Recall and Send Features
Introduction
Storing and Clearing Readings
Recalling Stored Readings
Using Send
Sleep Mode
5 Changing the Default Setting
Introduction
Selecting Setup Options
Saving Setup Options
6 Maintenance
A. General Service
B. Replacing the Fuses
C. Replacing the Battery
7 Specifications
Safety and Compliances
Physical Specifications
General Specifications
Feature Summary
Basic Specifications
Detailed Accuracy Specifications
A. DC Voltage
B. AC Voltage
C. DC Current
D. AC Current
E. Resistance
F. Continuity Test
G. Diode Test
H. Capacitance
I. Frequency
J. Temperature
Degrees Celsius
Fahrenheit
K. 4~20mA loop current
L. Power Measurement
Model VC940: OPERATING MANUAL
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List of Tables
Table Title Page
1-1 Unpacking Inspection
1-2 International Electrical Symbols
2-1 Rotary Switch Selections
2-2 Functional Buttons
2-3 Functions Vs Displays
2-4 Display Features
5-1 Setup Selections
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List of Figures
Figure Title Page
2-1 Meter Structure
2-2 Display Features
3-1 Voltages Measurement
3-2 Currents Measurement
3-3 Resistance Measurement
3-4 Continuity Test
3-5 Diode Test
3-6 Capacitance Measurement
3-7 Frequency / Duty Cycle Measurement
3-8 Temperature Measurement
3-9 Power Measurement
6-1 Fuse Replacement
6-2 Battery Replacement
Model VC940: OPERATING MANUAL
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Chapter 1
Before You Start
Overview
This Operating Manual covers information on safety and cautions. Please read the relevant information carefully and observe all the Warni ngs and Notes strictly.
Warning
To avoid electric shock or personal injury, read the “Safety Information” and “Rules for Safe Operation” carefully before using the Meter.
Digital Multimeter VC940 (hereafter referred to as “the Meter”) is a 39999 counts and 4 3/4 digits with steady operations, fashionable structure and auto ranging instrument. The
Meter has analog bar graph, ACV & ACA True RMS and full range overload protection.
The Meter not only can measure AC voltage and current, DC voltage and current, Resistance, Capacitance, Temperature, Frequency, Diodes, Continuity, 4~20mA Loop,
Max/Min, Relative Mode but also has Low Battery Display, Store, Recall, Data Hold, Automatic Power Off and power features.
Unpacking Inspection
Open the package case and take out the Meter. Check the items shown on Table 1-1 carefully to see any missing or damaged part:
Table 1-1. Unpacking Inspection
Item Description Qty
1 English Operating Manual 1 piece
2 Test Lead 1 pair
3
K-Type (nickel chromium ~
nickel silicon) Point Contact
Temperature Probe (It is only
suitable for measuring
temperature under 230
°C
1 piece
5 Alligator Clip 1 piece
6 RS232C interface cable 1 piece
7 CD-ROM (Installation Guide &
Computer Interface Software)
1 piece
8 9V Battery (NEDA 1604, 6F22,
006P)
1 piece
9 Power Adaptor 1 piece
In the event you find any missing or damage, please contact your dealer immediately.
Safety Information
This Meter complies with the standards IEC61010 safety measurement requirement: in pollution degree 2, overvoltage category (CAT. III 1000V, CAT.IV 600V) and double
insulation.
CAT. III: Distribution level, fixed installation, with smaller transient overvoltage than CAT. IV
CAT.
IV: Primary supply level, overhead lines, cable systems etc.
Use the Meter only as specified in this operating manual, otherwise the protection provided by the Meter may be impaired.
In this manual, a Warning identifies conditions and actions that may pose hazards to the user, or may damage the Meter or the equipment under test.
A Note identifies the information that user should pay attention to.
International electrical symbols used on the Meter and in this Operating Manual are explained on page XX.
Rules For Safe Operation
Warning
To avoid possible electric shock or personal injury, and to avoid possible damage to the Meter or to the equipment under test, adhere to the following rules:
z Before using the Meter inspect the case. Do not use the Meter if it is damaged or the case (or part of the case) is removed. Look for cracks or missing
plastic. Pay attention to the insulation around the connectors.
z Inspect the test leads for damaged insulation or exposed metal. Check the test leads for continuity. Replace damaged test leads with identical model
number or electrical specifications before using the Meter.
z Do not apply more than the rated voltage, as marked on the Meter, between the terminals or between any terminal and grounding.
z The rotary switch should be placed in the right position and no any changeover of range shall be made during measurement is conducted to prevent
damage of the Meter.
z When the Meter working at an effective voltage over 60V in DC or 30V rms in AC, special care should be taken for there is danger of electric shock.
z Use the proper terminals, function, and range for your measurements.
z If the value to be measured is unknown, use the maximum measurement position.
z Do not use or store the Meter in an environment of high temperature, humidity, explosive, inflammable and strong magnetic field. The performance of the
Meter may deteriorate after dampened.
z When using the test leads, keep your fingers behind the finger guards.
z Disconnect circuit power and discharge all high-voltage capacitors before testing resistance, continuity, diodes.
z Before measuring current, check the Meter’s fuses and turn off power to the circuit before connecting the Meter to the circuit.
z Replace the battery as soon as the battery indicator
appears. With a low battery, the Meter might produce false readings that can lead to electric shock
and personal injury.
z When servicing the Meter, use only the same model number or identical electrical specifications replacement parts.
z The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident.
z Soft cloth and mild detergent should be used to clean the surface of the Meter when servicing. No abrasive and solvent should be used to prevent the surface of
the Meter from corrosion, damage and accident.
z The Meter is suitable for indoor use.
z Turn the Meter off when it is not in use and take out the battery when not using for a long time.
z Constantly check the battery as it may leak when it has been using for some time, replace the battery as soon as leaking appears. A leaking battery will damage
the Meter.
International Electrical Symbols
Symbols used on the Meter and in this manual are explained in Table1-2.
Model VC940: OPERATING MANUAL
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Table 1-2. International Electrical Symbols
AC or DC
Grounding
Double Insulated
Warning. Refer to the Operating Manual
Deficiency of Built-In Battery
Conforms to Standards of European Union
Model VC940: OPERATING MANUAL
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Chapter 2
Getting Acquainted
Turning the Meter On
To turn the Meter on, turn the rotary switch from OFF to any switch setting.
Battery Considerations
The Meter uses one 9V Battery (NEDA 1604, 6F22, 006P). The following paragraphs describe several techniques used to conserve battery power.
Automatic Power Off
The display blanks and the Meter goes into a “sleep” mode if you have not changed the rotary switch position or pressed a button for a set period. While in Sleep mode,
pressing the blue button or turning the rotary switch could turn the Meter on. The Meter then returns to the display for the function selected with the rotary switch; all previously
activated button features are discarded.
The automatic power off is preset to 30 minutes. From the Setup menu (see Chapter 5), you could specify a time (10 minutes, 20 minutes, 30 minutes or OFF). If you set to
OFF, the Meter retains on until you turn the rotary switch to OFF or the battery becomes too weak.
Automatic Backlight Off
Press LIGHT button to turn the backlight on and press
LIGHT again to turn it off.
Press SELECT to select the backlight level (low or high). In Setup menu (see Chapter 5), you could specify a time to automatically turn off the backlight (10 seconds, 20
seconds, 30 seconds or OFF). If the period is set to OFF, the backlight feature is disabled.
Low Battery Indication
A constant battery icon ( ) in the upper left corner of the display notifies you that the batteries are low and should be replaced.
Warning
To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery icon (
) appears.
The Meter Structure
The Figure 2-1 shows the Meter structure.
1. LCD Display
2. Functional Buttons
3. Rotary Switch
4. Input Terminals
1
2
3
4
Figure 2-1. Meter Structure
Rotary Switch
Turn the Meter on by selecting any measurement function. The Meter presents a standard display for that function. The display may also be influenced by some of the choices
made in Setup.
Use the blue button to select any rotary switch alternate function (labeled in blue letters).
When you turn the rotary switch from one function to another, a display for the new function appears. Button choices made in one function do not carry over into another
function.
The Table 2-1 described each rotary switch position
Table 2-1. Rotary Switch Selections
Rotary
Switch
Position
Rotary Switch Function Blue Key Function
OFF Turn the Meter off None
DC voltage measurement
None
AC voltage measurement
None
Hz
DC millivoltage measurement
z Frequency measurement
z Frequency signal duty cycle
measurement
Resistance measurement
z Diode test
z Continuity test
Capacitance measurement
None
Centigrade temperature
measurement
Fahrenheit temperature measurement
µA
AC or DC current measurement
(400µA , 4000µA)
Toggle between AC or DC current
mA
(4~20mA)
%
AC or DC current measurement
(40mA , 400mA)
Toggle between AC or DC current
4~20mA loop current as % reading
A
AC or DC current measurement
(10A)
Toggle between AC or DC current
Model VC940: OPERATING MANUAL
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Functional Buttons
The buttons activate features that augment the function selected with the rotary switch. The buttons are shown in Table 2-2.
Press the button once to access the main feature (e.g. STORE).
To access the first additional feature of the button (e.g. RECALL), press and hold the button for over 1 second to access this additional feature. This additional feature appears
right above or on the left hand side of the appropriate keys.
To access the second additional feature of the button (e.g.
), press once the button again while the Meter has already entered the first additional feature (e.g. RECALL). The
second additional feature appears on the right hand side above the appropriate keys.
The RANGE and EXIT buttons has only one additional feature.
Table 2-2. Functional Buttons
Button Description Access Method
Range feature:
Exit AUTO and enter MANUAL ranging. In MANUAL, select
next input range. EXIT to return to AUTO. AUTO is default.
Press the button once.
Setup feature:
Access Setup selections, the display shows “SET”.
In the Setup mode, each press of SETUP button steps to the
next Selection
Press and hold the button for more
than 1 second
Store feature:
Store the current measurement value. Press EXIT to exit the
Store feature.
Press the button
once.
Recall feature:
Recall the stored value. Press EXIT to exit the Recall
feature.
Press and hold the button for over 1
second
Setup feature:
In Setup, press to select OFF at the selection of HIGH and
LOW
Press the button
once after entering Setup mode.
Hold feature:
Press HOLD to freeze the displayed value. Press EXIT to
release the display.
Press the button once.
Peak Hold feature:
Press to access Peak Hold feature, the primary display
shows PEAK HOLD. Press EXIT to exit.
Press and hold the button for over 1
second.
z In Setup, each press to select the digit you want to
edit.
z In Recall, press to enable SEND feature
z In Store, press to toggle between clearing all the
stored reading or start storing reading from the current
index number.
Press the button once after entering
Setup or Recall or Store mode.
Press to exit certain button functions Press the button once.
Press to turn the backlight on. It is possible to toggle
between 1
st
and the 2nd backlight and Exit the feature by
pressing the button. After exiting the light feature, it is
necessary to press and hold the button for over 1 second to
turn the backlight on again.
Press and hold the button for over 1
second.
Press to display max, min and average values.
Press EXIT to stop and return to current measurement mode.
Press the button once.
Press to output the data, AUTO mode switch off. The primary
display shows “SEND”.
Press EXIT to exit.
Press and hold
the button for over 1 second.
In Setup, each press to decrement an Option.
In Recall, each press to go back to the previous stored
reading.
In Store, each press to decrease a second on the storing
interval.
Press EXIT to exit
Press the button once after entering
SEND mode.
Press to enter relative mode, the primary display shows .
The left secondary display shows the present measurement
value. The right secondary display shows the stored value.
The primary display shows the present measurement value
minus the stored value.
Press EXIT to exit relative mode.
Press the button once.
In Setup, each press to increment an Option.
In Recall, each press to recall the next stored reading.
In Store, each press to increase a second on the storing
interval.
Press and hold the button for over 1
second.
Yellow Button
When it is at AC measurement mode, press the button to
display AC+DC True RMS value in the primary display and
the left secondary display “AC+DC”.
Press the button once
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