Grounding The Instrument - ABB LLT100 Operating Instructions Manual
Laser level transmitter oi-llt100-en rev. d
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- Operating instruction (4 pages) ,
- Functional safety manual (32 pages)
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3.4 Grounding the instrument
The LLT100 must be grounded in accordance with national
and local electrical codes, using the grounding terminal (PE)
by means of a short connection with an equipotential bonding.
The equipotential bonding conductor must have a maximal
cross-section of 4 mm
.
2
Star or daisy chains are not allowed under any circumstances.
Protective earth (PE) terminals are available inside and outside
the instrument housing (see Figure 5 on page 9). These
terminals are electrically connected.
When grounding the LLT100 with a shielded wire, connect
the wire to the PE terminal located inside the LLT100 housing.
That shield wire should only be grounded at one end, not both.
If using the external PE terminal, you MUST connect the wire
to the monitored vessel.
The most effective LLT100 case grounding method is direct
connection to earth ground with an impedance of 5 mOhm
or less.
Figure 4
External protective earth (PE) terminal
3.4.1
Surge protector-equipped terminal block
To ensure proper functioning, ground connection is mandatory
for surge protector-equipped instruments. An overloaded
instrument must be de-energized for at least 5 seconds.
CAUTION
Test voltage withstand capability can no longer be
ensured when this protective circuit is used.
Outside installations or installations exposed directly or
indirectly to lightning discharges shall have a secondary
lightning protection module. Use of a protected terminal
block in combination with a lightning arrestor module, both
properly grounded, is mandatory for the continuous protection
of installations and users. Refer to local building code and
electrical code for proper practices.
3.4.2 Common mode voltages
The LLT100 with surge protection will not work if exposed to
common mode voltage in excess of the maximum allowed
supply voltage.
Connectors available ONLY on LLT100
with heater option (2+2 wires)
External DC supply for
lens heater option:
+24 V, 3 W
Internal PE
Pos
terminal
( + )
Figure 5
LLT100 terminal compartment
(back of LLT100 unit, with cover off)
External PE
0 V (return)
terminal
Neg
External
M4 cover
( – )
meter
locking screw
(optional)
OI-LLT100-EN Rev. D | User Guide 9
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