Environmental Considerations; Power-Specific Considerations; Cable- And Cable Gland-Specific Considerations - ABB LWT300 series User Manual

Environmental considerations

The LWT should be installed in an area that is within its specified temperature range (see "Specifications"
on page A77), taking into consideration the enclosure ratings and the construction materials.
NOTICE
If the site where the LWT will be installed is subject to severe vibration conditions,
harsh environment errors might be flagged. Contact ABB for information on using a
remote coaxial probe installed on a bracket to dampen oscillations.
Hazardous area considerations
• LWT housings are certified as conforming to protection type IP68 (according to IEC 60529) or
Type 6P (according to NEMA).
• The external housing is not made to resist high pressures. Only the probe and coupler can come in
contact with the process.
• LWT instruments must only be installed in hazardous areas for which they are properly certified. The
certification plate is permanently fixed on the neck of the instrument head.

Power-specific considerations

• For maximum power supply voltage, refer to the instrument identification plate or see
"Specifications" on page A77.
• For signal and power loop connections up to 1500 meters (4900 feet) in length, use Ø 0.8 to
0.35 mm² (18 to 22 AWG) twisted, stranded pair wiring. Longer loops will require larger wires.
• The 4 – 20 mA DC output signal and the DC power supply to the LWT instrument are carried by the
same pair of wires.
• Supply voltage at the instrument terminals must be between 15.5 and 42 V DC. If using a 250 Ω resistor
for the HART connection, limits are between 21 and 42 V DC if there is no other load on the line.

Cable- and cable gland-specific considerations

WARNING
Cables, cable glands and unused port plugs must comply with the intended type of
protection (e.g., dust proof, flameproof, etc.) and degree of protection (e.g., IP68 or
Type 6P).
It is the costumers' responsibility to use appropriate cable glands, screw plugs, lubes
and/or sealants for the cable entry ports. ABB does not assume any responsibility
for non ATEX- or CE-certified cable glands or adapters that do not meet the above
requirements.
The installer assumes responsibility for any other type of sealing medium used.
In the particular case of explosion proof installations, remove the temporary plastic
caps and close the unused opening with a plug certified for explosion containment
with appropriate rating.
Wires and cable glands shall be rated to at least 90 °C.
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User Guide