Yokogawa EJA110A - Manual (Page 10)

IM 01C21B01-01E 2-2
2. HANDLING CAUTIONS
2.4 Selecting the Installation
Location
The transmitter is designed to withstand severe
environmental conditions. However, to ensure stable
and accurate operation for years, observe the following
precautions when selecting an 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
equipments, provide adequate thermal insulation
and/or ventilation.
(b) Ambient Atmosphere
Avoid installing the transmitter in a corrosive
atmosphere. If the transmitter must be installed in a
corrosive atmosphere, there must be adequate
ventilation as well as measures to prevent intrusion
or stagnation of rain water in conduits.
(c) Shock and Vibration
Select an installation site suffering minimum shock
and vibration (although the transmitter is designed
to be relatively resistant to shock and vibration).
(d) Installation of Explosion-protected Transmitters
Explosion-protected transmitters can be installed in
hazardous areas according to the types of gases for
which they are certified. See Subsection 2.9
“Installation of Explosion Protected Type Transmit-
ters.”
2.5 Pressure Connection
WARNING
• Instrument installed in the process is under
pressure. Never loosen the process connector
bolts to avoid the dangerous spouting of
process fluid.
• During draining condensate from the pressure-
detector section, take appropriate care to avoid
contact with the skin, eyes or body, or inhala-
tion of vapors, if the accumulated process fluid
may be toxic or otherwise harmful.
The following precautions must be observed in order to
safely operate the transmitter under pressure.
(a) Make sure that the four process connector bolts are
tightened firmly.
(b) Make sure that there are no leaks in the impulse
piping.
(c) Never apply a pressure higher than the specified
maximum working pressure.
CAUTION
Maximum working pressure of the model
EJA120A differential pressure transmitter is 50
kPa {0.5 kgf/cm
2 }.
Should the pressure exceed 50 kPa {0.5 kgf/
cm
2 }, it is possible to break the sensor. Proceed
with caution when applying 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 6.4.2a, 6.4.2b and 6.4.2c.)
2.7 Restrictions on Use of Radio
Transceiver
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 for such
effects, bring the transceiver in use slowly from a
distance of several meters from the transmitter,
and observe the measurement loop for noise
effects. Thereafter, always use the transceiver
outside the area affected by noise.
2.8 Insulation Resistance and
Dielectric Strength Test
Since the transmitter has undergone insulation resis-
tance and dielectric strength tests at the factory before
shipment, normally these tests are not required.
However, if required, observe the following precau-
tions in the test procedures.
(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.
(b) Never apply a voltage exceeding 500 V DC (100 V
DC with an internal lightning protector) for the
insulation resistance test, nor a voltage exceeding
500 V AC (100 V AC with an internal lightning
protector) for the dielectric strength test.