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Reference Manual
300530EN, Rev BA
September 2012
3-11
Rosemount 2410
Section 3. Installation
Example 2
The second example, illustrated in Figure 3-3, includes two tanks with a
Rosemount 2410 Tank Hub acting as power supply to the field devices on
both tanks.
The first tank is located 300 m away from the 2410 Tank Hub and the second
tank a further 350 m away.
Both tanks have two field devices: a Rosemount 5400 Radar Level
Transmitter and a Rosemount 644 Temperature Transmitter. The total current
consumption of the two devices is 32 mA (see Table 3-2).
Figure 3-3. Example installation
with two tanks
The total operating current of the connected field devices on the two tanks is
32+32 mA=64 mA. This is within the output capability of the Rosemount 2410
Tank Hub.
Voltage drop to the first tank:
64 mA x 0.30 km x 42 /km=0.80 V.
Voltage at first tank =12.5 V - 0.80 V=11.70 V.
Voltage drop between first and second tank:
32 mA x 0.35 km x 42 /km=0.47 V.
Voltage at second tank =12.5 V - 0.80 V - 0.47 V=11.23 V.
For both tanks the input voltage to the field devices is above the minimum
requirement of 9 V.
The field devices may be connected to the Tankbus via segment couplers as
illustrated in Figure 3-3. The spur length must not exceed 60 m according to
the FISCO standard. In the example above, it is assumed that the voltage
drop between the segment coupler and the devices can be ignored.
2410 Tank Hub with
intrinsically safe power
supply:12.5 V, 250 mA
5400 Radar Level
Transmitter
644 Temperature
Transmitter
300 m
350 m
Voltage drop=0.80 V Voltage drop=0.47 V
Segment
coupler
Tankbus
(Spur <60 m)
(Spur <60 m)
Segment
coupler