KROHNE TIDALFLUX IFM 4110 PF EN - Manual (Page 10)

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8 Outer sheath
Bootstrap signal cable type BTS
The signal converter automatically controls the individual shields (3) to exactly the same voltage as that applied to the signal wires
(5). Since the voltage difference between signal wires (5) and individual shields (3) is virtually zero, there is no flow of current via
the line capacitance 3+5; thus, line capacitance is apparently zero. Much longer cable lengths are then permitted for fluids with
low electrical conductivity levels.
1 Dummy glider wire
2 Insulation
3 Special foil, 1
st
shield
4 Insulation
5 Stranded wire 0.5 mm
2
(20 AWG)
6 Stranded drain wire, 1
st
shield, 0.5 mm
2
(20 AWG)
7 Special foil, 2
nd
shield
8 Stranded drain wire, 2
nd
shield, 1.5 mm
2
(14 AWG)
9 Insulation
10 Mu-metal foil, 3
rd
shield
11 Stranded drain wire, 3
rd
shield, 0.5 mm
2
(20 AWG)
12 Outer sheath
1.5.4 Field current cable
The cross-section of the field current cable (standard not included) is dependent on the length that is required:
length Cross-section
0 – 150 m (0 – 500 ft) 2 x 0.75 mm
2
Cu (2 x 18 AWG)
150-300 m (500 – 1000 ft) 2 x 1.5 mm
2
Cu (2 x 14 AWG)
300 – 600 m (1000 – 2000 ft) 4 x 1.5 mm
2
Cu (4 x 14 AWG)
1.5.5 Cable lengths: max. allowed distance between primary head and signal converter
•
Determining the maximum permissible distance between primary head and signal converter
1. The length of signal cable is dependent on the electric conductivity of the liquid product and of the type of cable used.
For BTS cable (optional) the maximum length is 600 m, independent of the conductivity.
For DS cable (standard) the maximum length is as followes:
electr. conductivity
γ
[
µ
S/cm]
max. length
[m]
50 120
100 200
200 400
400 600
2. The length of field current cable is determined by the cable cross-section A
F
, see sect. 1.5.4.
3. The length of the data interface cable must not exceed 600 m.
4. The shortest cable length obtained either according to Point 1, 2 or 3 is the maximum permissible distance between
primary head and signal converter!
1.5.6 Connection diagram IFC 110 PF with IFS 4000 PF
In the following diagram you can see how to connect the two devices with each other. In this diagram the data interface cable
is called “Q”, the field current cable is “C” and the electrode cable is “DS”.
1
2
3
4
5
6
7
8
9
10
11
12