Emerson Process Management Rosemount 2410 manual Reference Manual, Example, Radar Level, Segment

Reference Manual

300530EN, Rev BA September 2012

Rosemount 2410

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

2410 Tank Hub with	5400 Radar Level
	Transmitter
intrinsically safe power
supply:12.5 V, 250 mA

Tankbus

300 m

Voltage drop=0.80 V

<60 m)	644 Temperature	<60 m)
(Spur		(Spur
	Transmitter
	350 m
Segment		Segment
coupler		coupler
	Voltage drop=0.47 V

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 Ω/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 Ω/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.

Section 3. Installation 3-11