Chapter II
5000-count portable digital multimeter, with current input
17
∗
When the multimeter is linked to measurement circuits, do not touch unused
terminals.
∗
When the range of the value to be measured is unknown, check that the range
initially set on the multimeter is the highest possible or, wherever possible, choose
the autoranging mode.
∗
Before changing functions, disconnect the test leads from the circuit under test.
∗
In TV repair work, or when carrying out measurements on power switching circuits,
remember that high amplitude voltage pulses at the test points can damage the
multimeter. Use of a TV filter will attenuate any such pulses.
∗
Never perform resistance or continuty measurements on live circuits.
1.1.3. Symbols
Symbols used in this manual and on the instrument :
CAUTION : Refer to the instruction manual.
Incorrect use may result in damage to the device or its components.
DANGER : High voltage, risk of electric shock.
Earth
1.1.4. Instructions
∗
Before opening up the instrument, always disconnect from all sources of electric
current and make sure you are not charged with static electricity, which may destroy
internal components.
∗
Fuses must be replaced with fuses of the same rating and type.
∗
Any adjustment, maintenance or repair work carried out on the multimeter while it is
live should be carried out only by appropriately qualified personnel, after having
taken into account the instructions in this present manual.
A "qualified person" is someone who is familiar with the installation, construction
and operation of the equipment and the hazards involved. He is trained and
authorized to energize and de-energize circuits and equipment in accordance with
established practices.
∗
When the instrument is opened up, remember that some internal capacitors can
retain a dangerous potential even after the instrument is switched off.
∗
If any faults or abnormalities are observed, take the instrument out of service and
ensure that it cannot be used until it has been checked out.
∗
It is recommended to remove the battery from the instrument if not used.
1.2. Protection
mechanisms
This instrument is fitted with various protection mechanisms :
∗
Varistor protection for limiting transients of over 1100 V at the V
Ω
terminal,
particularly 6 kV pulse streams as defined by the French standard IEEE 587.
∗
A PTC (positive temperature coefficient) resistor protects against permanent
overvoltages of up to 600 V during resistance, capacitance, continuity and diode
test measurements. This protection is reset automatically after overload.
