MULTI MEASURING INSTRUMENTS VD-320 Instruction Manual

DIGITAL VOLTAGE CHECKER

MODEL VD-320

INSTRUCTION MANUAL

Thank you very much for selecting our voltage checker model VD-320.
This model is complex instrument and employ a very reliable
mechanical/electronic design.
Before you use your new instrument, read this Instruction Manual
completely and familiarize yourself thoroughly with all functions.
With proper use and care, your tester will give you years of
satisfactory service.

FEATURES

● Only one point contact for AC/DC voltage measurement to avoid the short circuit.

● High input impedance for safe operation.

● Polarity display for DCV measurement.

● For the identification of hot line or earth line for ACV circuit.

● Useful one hand operation and data hold function.

● Auto power off function is provided.

SAFETY SUMMARY

The WARNINGs which appear on the following page must be followed to ensure operator

safety and to retain the operating condition of the tester.

Safety Symbols:
Indicates the operator must refer to an explanation in this manual.
Indicates terminals at which dangerous voltages may exist.

WARNING
* Do not make voltage measurements of power lines carrying more than 250V.
In some cases, power lines may carry voltage spikes of several times of the normal

supply voltage. This tester should not be used to measure power lines.

* Possible Electrical Shock or Fire Hazard
Do not expose this tester to rain or moisture. Do not operate the tester in the presence

of flammable gases or fumes.
Always check to make sure that the function switch is set to the proper position.
When making measurements, use CAUTION as dangerous voltages may be present in

normally safe areas.
To avoid electrical shock, use CAUTION when working above 60V DC or 25V AC rms.

Such voltages pose a shock hazard.
Never make measurements with the battery cover off.
Never fail to keep the maximum tolerable input.
This tester is designed for low voltage applications. To avoid electrical shock or

damage, the measurement is limited to the circuit under 500V AC or 400V DC.
Never operate this instrument if it becomes wet, damp or has any liquid condensation

build-up on any part of the instrument.

SPECIFICATIONS

Measuring function: DC voltage, AC voltage
Display: 3 digit LCD max. reading of 1999 with annunciators
Measuring ranges: DC voltage 0~200V/400V, AC voltage 0~500V (50 or 60Hz)
Over range indication: Blanking of all digits except MSD 1
Low battery indication: “B” mark on LCD readout
Sampling: 2 times/sec.
Data hold indication: “DH” mark on LCD readout
Auto power off: The meter is set to power off mode approx. 10 minutes after the power

switch on.

Withstanding voltage: AC 2200V/1 minute (between rubber probe tip and conductive

rubber holder)

Limitation of circuit voltage: Less than AC/DC 600V
Insulation resistance: 10MΩ or more (between rubber probe tip and conductive holder)
Operating temperature: 0℃～40℃, <80% RH
Storage temperature: -10℃～60℃, <70% RH
Power supply: SR-44 (1.55V) x 2 or LR-44 x 2
Battery life: Approx. 60 hours continuous (by LR-44)

Size/Weight: 34(W) x 153(H) x 24(D) mm, approx. 50g
Accessories: Soft case...1, Instruction manual...1, Batteries...2

Accuracy (23℃±5℃, less than 80%RH and at bare terminal)

Range

Resolution

Accuracy

Polarity/Display

ACV

1V

±5%rdg±5dgt

Hot line: voltage, Earth line: no display

DC 200V
DC 400V

0.1V
1V

±5%rdg±5dgt

Positive: +, Negative: -

*Measurement on the coated cable
DC Voltage: Display general approximate value after 30sec. contact.
AC Voltage: Display general approximate value at once.

PANEL FUNCTION

① Sensing tip
② Range switch
③ Power switch
④ Reset (discharge) switch
⑤ Data hold switch
⑥ LCD (display)
⑦ Conductive holder
⑧ Battery cover
⑨ Hand strap

24

⊕

⊖

CAUTION BEFORE OPERATION
* VD-320 is for use with low power lines. Do not use it with high power lines.

* Contact the sensing tip firmly to the object to be measured.
* If VD-320 is used nearby noise generating equipment, or the equipment to be

measured is not grounded, be aware that the display may become unstable or indicate

large errors.
* The conductor in the shielded pipe cannot be measured.
* Always discharge the electrostatic capacity of the sensing tip before measurement.
* For the measurement of the insulated conductor or cable, the measured value may

indicate large errors and more than 30sec. of contact is necessary to get the displayed

value.

METHOD OF MEASUREMENT
DCV Measurement

① Press the power switch to ON.
② Set the range switch to a range appropriate to the object to be measured.
③ Discharge the electrostatic capacity of the meter.
Touch to the sensing tip by the fingers of the left hand and hold the unit body by right

hand and press the reset switch as following figure:

Hold the unit body with right hand

When “000” is displayed, release the reset switch.

④ Hold the unit body and contact the sensing tip firmly to the conductor or object under

test and read the displayed value.

⑤ If you make measurements in a dark place or in a place where it is difficult to see the

readings, use the data hold switch. After measurement, turn the power switch to OFF.

The power is automatically turned to OFF, 10 minutes after the power switch ON.
Examples:

Battery Voltage DC Power Supply

Battery

Display appears

Display will appear by the contrary way

ACV Measurement

① Press the power switch to ON.
② Set the range switch to ACV range.
③ Discharge the electrostatic capacity of the meter.
④ Hold the unit body and contact the sensing tip firmly to the conductor or object under

test and read the displayed value.

If you cannot get the stable reading, touch to the floor or wall with left hand.

Left Hand

Right Hand
Left Hand

Right Hand

(Touch the flame

with left hand)

Touch to the floor or
wall with left hand

Hold the unit body with right hand

⑤ If you make measurements in a dark place or in a place where it is difficult to see the

readings, use the data hold switch.
After measurement, turn the power switch to OFF.
The power is automatically turned to OFF, 10 minutes after the power switch ON.

NOTE FOR OPERATION

* In single-phase or three-phase electric circuit, the one of the conductors is earthed.
The earthed conductor cannot be detected. Make measurement with another conductor.
* If the data hold switch was set to ON, the measurement is not operative.
Set the data hold switch to OFF before measurement.
* When making measurement for the extended cord connected with receptacle or when

measuring for insulated conductors, be aware that the display indicates lower value.

REPLACEMENT OF BATTERY

When the battery becomes exhausted or drops below the operating voltage, “B” mark is
displayed. Turn the power switch to OFF prior to installing batteries.
To install batteries, remove the battery cover
located on the unit back.
Insert the two LR-44 or SR-44 into the battery
Case making sure that proper polarity is observed.
Always replace both batteries at the same time.
If the difference between the voltage of the batteries is
big, the measurement error may be caused. Set + side to the upper

WARRANTY

This instrument is sent out from our factory after the sufficient internal inspections
but if you find any defect due to the fault in our workmanship or the original parts,
please contact the dealer where you bought the instrument.

The warranty period is 12 months from the date of purchase and the instrument shall be
repaired at free of charge, provided that we judge the cause of defect is obviously resulted
from our responsibility.

MULTI MEASURING INSTRUMENTS CO.,LTD.
Akihabara Murai Bldg. 7F, 1-26 Kanda Sakuma-cho,
Chiyoda-ku, Tokyo, 101-0025 Japan
TEL : [phone] FAX : [phone]
Home Page : http://www.multimic.com/
E-mail : [e-mail]