14 User Guide
Environmental considerations
The LWT should be installed in an area that is within its specified temperature range, 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 (see “Setting process conditions” on page 50).
Contact ABB for information on using a remote coupler installed on a bracket to dampen
oscillations (see “Installing a remote head LWT instrument” on page 24).
Hazardous area considerations
• LWT housings are certified as conforming to protection type IP 66/68 (according to IEC 60529) or
Type 4X/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 considerations
• For maximum power supply voltage, refer to the instrument identification plate.
• For signal and power loop connections up to 1200 meters (4000 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.
• Supply voltage at the instrument terminals must be between 10.5 and 28.5 V DC.
• Typical power consumption is below 30 mW.
Cable- and cable gland 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 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 100 °C.
NOTICE
The LWT instrument has a ½-inch NPT/M20 cable gland entry.
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