Emerson Rosemount 2230 Reference Manual page 30

Installation
March 2021
Note
When grounding the display via threaded conduit, make sure the connection provides
sufficient low impedance.
Grounding - F
Signal wiring of the fieldbus segment can not be grounded. Grounding out one of the
signal wires may shut down the entire fieldbus segment.
Shield wire connection
To protect the fieldbus segment from noise, grounding techniques for shield wire usually
require a single grounding point for shield wire to avoid creating a ground loop. The
ground point is typically at the power supply (Rosemount 2410 Tank Hub).
The Rosemount Tank Gauging devices are designed for "daisy-chain" connection of shield
wiring in order to enable a continuous shield throughout the Tankbus network. The shield
wire terminal in the Rosemount 2230 is not connected to ground. It merely provides
electrical continuity to daisy-chained Tankbus cables.
3.4.3 Cable selection
Use shielded twisted pair wiring for the Rosemount 2230 in order to comply with FISCO
requirements and EMC regulations. The cables must be approved for use in hazardous
areas, where applicable. In the U.S. explosion-proof conduits may be used in the vicinity of
the vessel.
We recommend cable size 0.75 mm
the range 22 AWG to 16 AWG (0.5 to 1.5 mm
voltage drop to the Rosemount 2230 display.
Tankbus cabling must be approved for use in minimum 85°C to match requirements for all
devices in a Rosemount Tank Gauging system.
The FISCO specification requires that cables for the Tankbus comply with the following
parameters:
Table 3-1: FISCO Cable Parameters
Parameter
Loop resistance
Loop inductance
Capacitance
Maximum length of each spur
Maximum cable length including trunk
spurs
(1) For further information see requirements of the IEC 61158-2 standard
(2) A spur is an unterminated part of the network.
(6) See IEC 61158-2 and IEC/TS 60079-27:2002.
30
™
OUNDATION
(1)
(2)
cable
Fieldbus
2
(18 AWG) in order to facilitate wiring. Cables within
2
) can be used in order to minimize the
Value
15 Ω/km to 150 Ω/km
0.4 mH/km to 1 mH/km
45 nF/km to 200 nF/km
60 m in apparatus class IIC and IIB
(3)
and 1000 m in apparatus class IIC and 1900 m in
apparatus class IIB
Reference Manual
00809-0100-2230
(6)
Reference Manual