MR8740、MR8741_user_manual_eng_20191016H.pdf - 第22页

Operating Precau tions 10 • Before transporting the instrument, di sconnect all cab les and USB memory sticks. • When there is no input, the waveform might be unst able due to the induced voltage, but th is is not an err…

Operating Precautions

Handling the Instrument and Modules

• Do not exceed the range of the specifications and the rated value of the cable

or the module. Otherwise, the instrument may be damaged or may produce

heat, resulting in personal injury.

The maximum rated voltage to earth does not change when an attenuator or

similar is used at the input. Take the connection method into consideration and

make sure that the rating is not exceeded.

• To avoid electric shock, do not remove the instrument’s cover and the module

case.

The internal components of the instrument carry high voltages and may

become very hot during operation.

• It is recommended to measure the secondary side of a distribution panel with

the U8974 High Voltage Unit. Do not connect the connection cords on the pri-

mary side of the distribution panel because an unrestricted current flow can

damage the connection cords and facilities if a short-circuit occurs.

• Each channel of Model U8979 Charge Unit has the BNC terminal and minia-

ture connector terminal with the common ground. Do not connect cords with

each of the terminals simultaneously to avoid a short-circuit.

• Setting the measurement mode to [PreAmp] allows Model U8979 Charge Unit

to constantly provide power (3.5 mA, 22 V) to sensors. Set any measurement

mode other than [PreAmp] or tum off the instrument before connecting a sen-

sor or probe with a BNC terminal to avoid an electric shock or damage to the

measurement target.

• To avoid electric shocks, confirm that the instrument is turned off and the con-

nection cables are disconnected before removing or replacing a module.

• To avoid electric shocks, do not operate the instrument with a module

removed.

To use the instrument after removing a module, install a blank panel over the

opening of the removed module.

• To prevent instrument damage or electric shocks, use only the screws for

securing the module in place that shipped with the instrument.

If you lose any screw or find that any screws are damaged, please contact

your Hioki distributor for a replacement.

• Model U8979 Charge Unit has miniature connectors with the maximum input

charge of ±500 pC (for six higher-sensitivity range) or ±50,000 pC (for six

lower-sensitivity range). Inputting a charge that exceeds these value causes

damage to the instrument.

• Use an acceleration sensor with a built-in pre-amplifier that conforms to the

specification of Model U8979 (3.5 mA, 22 V). Using a inapplicable sensor may

cause damaging itself.

• To avoid damage to the instrument, protect it from physical shock when trans-

porting and handling. Be especially careful to avoid physical shock from drop-

ping.

• The mounting screws must be firmly tightened or the module may not perform

as specified or may fail.

• To avoid damaging modules, do not touch the module connectors on this

instrument.

Operating Precautions

• Before transporting the instrument, disconnect all cables and USB memory

sticks.

• When there is no input, the waveform might be unstable due to the induced

voltage, but this is not an error.

• This instrument may cause interference if used in residential areas. Such use

must be avoided unless the user takes special measures to reduce electro-

magnetic emissions to prevent interference to the reception of radio and televi-

sion broadcasts.

Handling Media

• Do not remove the media while it is being accessed by the instrument. Data on

the media could be lost.

• Do not turn off the power to the instrument while the media is being accessed

by the instrument. Data on the media could be lost.

• Do not transport the instrument while a USB flash drive is connected. Damage

could result.

• If damage occurs to the data on the media, we cannot restore or analyze the lost

data. No compensation will be provided, regardless of the type or cause of the

problem or damage.We therefore recommend maintaining a backup of any

important data.

• Be careful to avoid inserting a media backwards or upside-down. The media or

the instrument could be damaged.

• Never insert or eject a media while it is being accessed by the instrument. Data

on the media could be lost.

• Do not operate the instrument at a slanted angle. It may not work properly.

• Do not transport the instrument while a USB memory stick is connected. Dam-

age could result.

• Some USB memory sticks are susceptible to static electricity. Exercise care

when using such products because static electricity could damage the USB

memory stick or cause malfunction of the instrument.

• With some USB devices, the instrument may not start up if power is turned on

while the device is inserted to the USB port. In such a case, turn power on first,

and then insert the USB device. It is recommended to try out operation with a

USB memory stick before starting to use it for actual measurements.

• Peculiar USB memory requiring fingerprint authentication or password cannot be

used.

• When saving or loading data, insert the storage media before selecting it. If the

media is not inserted, the file list display will not appear.

• All media (USB memory) have a limited service life. After extensive use over a

long period, data retention and readout may become stop working. In that

case, replace the card with a new one.

• Automatic saving of data is possible only on USB memory stick media.

• The data can be automatically stored in the USB flash memory; however, it is

not guaranteed to work.

Operating Precautions

Before Connecting Cables

When measuring power line voltage

• Connecting cables should only be connected to the secondary side of a

breaker Even if there is a short circuit on the secondary side of the breaker, the

breaker cuts off the electric supply. Do not connect to the primary side of a

breaker because unrestricted current flow could damage the instrument and

facilities if a short circuit occurs.

• To prevent electrical shocks and personal injury, do not touch any input termi-

nals on the VT (PT), CT or the instrument when they are in operation.

• Do not permanently connect the instrument in an environment where voltage

surges exceeding the maximum input voltage may occur. Applying voltage

may result in damage to the instrument, or a serious accident.

• Do not short-circuit two wires to be measured by bringing the connection

cables into contact with them. Arcs or such grave accidents are likely to occur.

• To avoid short circuit or electric shock, do not touch the metal parts of the con-

necting cable clips.

• To avoid electrical shocks, be careful to avoid shorting live lines with the con-

nection cable clips.

• To avoid electric shock and short-circuit accidents, use only the specified test

leads to connect the instrument input terminals to the circuit to be tested.

• To prevent an electric shock, confirm that the white or red portion (insulation

layer) inside the cable is not exposed. If a color inside the cable is exposed, do

not use the cable.

• The cable is hardened under the 0°C (32°F) or colder environment. Do not

bend or pull cables in such environments to avoid tearing insulation or break-

ing the cable.

•

Connecting to the BNC jacks on modules

Do not use a metal BNC connector. If you connect a metal BNC cable to an

insulated

BNC connector, the insulated BNC connector can be damaged and the instru-

ment may be damaged.

• To prevent cable damage, do not step on the cable or pinch them between

other objects. Do not bend or pull cables at their base.

• Use only the specified connection cables. Using a non-specified cable may

satisfy the specification requirements due to poor connection or other reasons.

• For detailed precautions and instructions regarding connections, refer to the

instruction manuals for your modules, connection cables, etc.