Emerson Rosemount 2230 User Manual

Page of 80
Reference Manual 
300560EN, Rev AA
May 2011
3-7
Rosemount 2230
Section 3. Installation
Grounding - F
OUNDATION
™ Fieldbus
Signal wiring of the fieldbus segment must not be grounded. Grounding one 
of the signal wires will 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 Raptor 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 2230 is not connected to ground. It only provides 
electrical continuity to daisy-chained Tankbus cables. 
3.3.3
Cable Selection 
for the Tankbus
Use shielded twisted pair wiring for the Rosemount 2230 in order to comply 
with FISCO
(1)
 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
2
 (18 AWG) in order to facilitate wiring. 
However, cables within the range 22 AWG to 16 AWG (0.5 t o1.5 mm²)
 
in 
order to minimize the voltage drop to the 2230 display.
Tankbus cabling must be approved for use in minimum 85°C to match 
requirements for all devices in a Raptor system.
The FISCO specification requires that cables for the Tankbus comply with the 
following parameters:
Table 3-1.  FISCO cable 
parameters
3.3.4
Hazardous Areas
When the Rosemount 2230 is installed in a hazardous area, national and 
local regulations and specifications in applicable certificates must be 
observed, see Appendix B: Product Certifications.
3.3.5
Power 
Requirements
The Rosemount 2230 is powered over the intrinsically safe Tankbus by the 
Rosemount 2410 Tank Hub. The 2410 feeds the intrinsically safe fieldbus 
segment by acting as a FISCO power supply on the Tankbus (9 - 17.5 Vdc, 
polarity insensitive).
See the Rosemount 2410 Reference Manual (Document no. 305030EN) for 
more information.
(1)
See IEC 61158-2 and IEC/TS 60079-27:2002.
Parameter
Value
Loop resistance
15
/km to 150/km
Loop inductance
0.4 mH/km to 1 mH/km
Capacitance
45 nF/km to 200 nF/km
Maximum length of each spur cable
60 m in apparatus class IIC and IIB
Maximum length of each trunk cable
1000 m in apparatus class IIC and 1900 m in 
apparatus class IIB