Level Plus
®
LevelLimit
®
Operation Manual
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18
I
Fig. 11: Tree topology
Fig. 12: Daisy-chain topology
the main difference of having a common junction box for all of the
transmitters as shown in Fig. 113. Bus with spurs and tree topologies
can also be used together to form a hybrid topology.
Daisy chain
The daisy-chain topology utilizes a single cable that is connected to
all of the transmitters with the cable being interconnected at each field
device. When using this topology make sure that the wiring practice
allows for one transmitter to be disconnected without disconnecting
the entire loop as shown in Fig. 124. MTS does not suggest using the
daisy-chain topology.
PLC
PLC
Fig. 13: Electrical conduit installation
Table 2: Cable specification and parameters
Table 3: Cable specifications Digital I/O
7.4 Cable recommendations
Refer to ‘Table 2’ below for general requirements of cable types for the
Level Plus
®
LevelLimit
®
analog transmitter.
Cable specifications Modbus communication
7.5 Electrical conduit
Parameter
Specifitcation
Minimum cable size
Ø
0.51…1.6 mm (24…14 AWG)
Cable type
Single pair shielded or multiple pair with
overall shield; minimum 0.25 mm (0.010 in.)
insulation thickness
Capacitance
Less than 98 pF/m (30 pF/ft)
Cable Type
Cat5 or equivalent type cable
Capacitance
Less than 15 pF/ft. (49 pF/m)
NOTICE
1. Tighten housing cover (both front and back covers if dual cavity)
to full stop against the O-ring.
2. Do not over-tighten compression fittings.
3. Use side conduit entry only.
4. In high humidity areas, use a breather drain type conduit sealing
fitting to minimize moisture intrusion.
5. For Division Installations, an approved conduit seal is required
within 457 mm (18 in.) of the enclosure.
6. For Zone Installations, an approved conduit seal is required within
50 mm (2 in.) of the enclosure.
Conduit sealing fitting
NPT or BSPP Fitting
Do not over-tighten
compression fitting!
Interface float
(ordered
separately)
Product float
(ordered
separately)
View shown with
cover removed
Plugged entry
Do not use
(see notes)
3/4 NPT or M20 conduit access
Use NPT conduit fitting only!
Conduit
(flexible or rigid)
Conduit from
control room
Level Plus
®
Do not remove cover with circuit energized in
hazardous locations!
Follow safe work procedures.
Cable specifications Digital I/O
