Yokogawa EJX118A - Manual (Page 10)

<2. Handling Cautions>
2-2
IM 01C25H01-01E
2.4 Selecting the Installation
Location
The transmitter is designed to withstand severe
environmental conditions. However, to ensure
that it will provide years of stable and accurate
performance, take the following precautions when
selecting the installation location.
(a) Ambient Temperature
Avoid locations subject to wide temperature
variations or a significant temperature gradient.
If the location is exposed to radiant heat from
plant equipment, provide adequate thermal
insulation and/or ventilation.
(b) Ambient Atmosphere
Do not install the transmitter in a corrosive
atmosphere. If this cannot be avoided, there
must be adequate ventilation as well as
measures to prevent the leaking of rain water
and the presence of standing water in the
conduits.
(c) Shock and Vibration
Although the transmitter is designed to be
relatively resistant to shock and vibration, an
installation site should be selected where this is
kept to a minimum.
(d) Installation of Explosion-protected Transmitters
An explosion-protected transmitters is
certified for installation in a hazardous area
containing specific gas types. See subsection
2.9 “Installation of an Explosion-Protected
Transmitters.”
2.5 Pressure Connection
CAUTION
• Never loosen the process flange bolts when
an instrument is installed in a process. The
device is under pressure, and a loss of seal
can result in a sudden and uncontrolled
release of process fluid.
• Since the accumulated process fluid may be
toxic or otherwise harmful, take appropriate
steps to prevent the contact of such fluids
with the skin or eyes and the inhalation
of vapors from these fluids even after
dismounting the instrument from process line
for maintenance.
The following precautions must be observed
in order to safely operate the transmitter under
pressure.
(a) Make sure that there are no leaks in the impulse
piping.
(b) Never apply a pressure higher than the
specified maximum working pressure.
2.6 Waterproofing of Cable
Conduit Connections
Apply a non-hardening sealant to the threads
to waterproof the transmitter cable conduit
connections. (See figure 5.8, 5.9 and 5.10.)
2.7 Restrictions on Use of Radio
Transceivers
IMPORTANT
Although the transmitter has been designed to
resist high frequency electrical noise, if a radio
transceiver is used near the transmitter or its
external wiring, the transmitter may be affected
by high frequency noise pickup. To test this, start
out from a distance of several meters and slowly
approach the transmitter with the transceiver
while observing the measurement loop for noise
effects. Thereafter use the transceiver outside
the range where the noise effects were first
observed.
2.8 Insulation Resistance and
Dielectric Strength Test
Since the transmitter has undergone insulation
resistance and dielectric strength tests at the factory
before shipment, normally these tests are not
required. If the need arises to conduct these tests,
heed the following:
(a) Do not perform such tests more frequently than
is absolutely necessary. Even test voltages that
do not cause visible damage to the insulation
may degrade the insulation and reduce safety
margins.