UEi Test Instruments DM384 - Manual (Page 7)

Measuring AC Voltage
WARNING!
To avoid the risk of electrical shock and instrument damage, input
voltages must not exceed the limits specified for the installation
category you are working in. DO NOT attempt to take any unknown
voltage measurements that may exceed these values.
Note: When taking voltage measurements your meter must be
connected in parallel to the circuit element, under test.
To measure AC volts plug in the test leads as instructed, then:
1. Turn off the meter.
2. Select the AC volt “ACV” position on the rotary function switch.
• If you do not know the maximum value of the voltage to be
measured, (within this meter’s category specific rating) allow
the meter to auto-range
3. Connect the test leads across the test-points of the circuit to be tested.
4. Read the measured voltage on the display.
Measuring Hertz (Frequency - Hz)
Use the Hertz function to determine the frequency of main power,
generators, inverters and electronic circuits. Different terms are used to
describe Hertz. Some of these are:
• Frequency of oscillation / Frequency / freq.
• Cycles per second / Cycles / CPS
• Hz
Note: When measuring frequency your meter must be connected in
parallel to the circuit, or circuit element, under test.
To measure frequency, plug in the test leads as instructed, then:
1. Turn on the multimeter.
2. Select the “Hz” position on the rotary function switch.
3. Connect the test leads across the circuit to be tested.
4. Read the measured frequency on the display.
Measuring Amps
Current flow is measured in amperes or “amps”, which indicates the
volume of electrons that pass through a given point. When taking
current measurements, this meter must be connected in series with
the circuit (or circuit element) under test.
CAUTION!
Never connect the test leads across (in parallel with) a voltage source
when attempting to measure current. This can cause damage to the
circuit under test or this meter.
Note: To measure current, you must create a break in the circuit under
test and make the meter part of the circuit. Two connection points are
created when a circuit is broken. On one side is the power source and
the other is the load.
To measure AC or DC current flow, (in amps), insert the test leads into
the meter as instructed, then:
1. Ensure power is off to the circuit to be tested.
2. Turn the meter on.
3. Select the AC or DC amp position on the rotary function switch.
4. Break the circuit as described earlier and connect the meter leads
to the points created by the break.
5. Apply power to the circuit.
6. Read your measurement value.
Note: When performing flame safeguard testing (a low DC amperage
test) on some gas furnace models, an adapter (sold by UEi) can be
placed in-line with the flame sensor to make testing fast and easy.
Note: When measuring DC current, A minus sign will be displayed if
the current is flowing opposite to the connection polarity.
Note: As a safety discipline, disconnect power to the circuit under test
before removing either test lead.
M a i n t e n a n c e
Periodic Service
WARNING!
Repair and service of this instrument is to be performed by qualified
personnel only. Improper repair or service could result in physical
degradation of the meter. This could alter the protection from
electrical shock and personal injury this meter provides to the
operator. Perform only those maintenance tasks that you are
qualified to do.
These guidelines will help you attain long and reliable service from
your meter:
• Calibrate your meter annually to ensure it meets original
performance specifications
• Keep your meter dry. If it gets wet, wipe dry immediately.
Liquids can degrade electronic circuits
• Whenever practical, keep the meter away from dust and
dirt that can cause premature wear
• Although your meter is built to withstand the rigors of daily
use, it can be damaged by severe impacts. Use reasonable
caution when using and storing the meter
Cleaning
Periodically clean your meter’s case using a damp cloth. DO NOT use
abrasive, flammable liquids, cleaning solvents, or strong detergents as
they may damage the finish, impair safety, or affect the reliability of the
structural components.
DM384-MAN P. 6