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Reference Manual
300530EN, Rev BA
September 2012
Rosemount 2410
3-6
Section 3. Installation
3.4.4 Grounding The housing should always be grounded in accordance with national and
local electrical codes. Failure to do so may impair the protection provided by
the equipment. The most effective grounding method is direct connection to
earth ground with minimal impedance. There are grounding screw
connections inside the terminal compartments which are identified by ground
symbols: / . There is also a grounding screw on the housing.
NOTE!
Grounding the device via threaded conduit connection may not provide
sufficient ground.
Grounding - Foundation Fieldbus
Signal wiring of the fieldbus segment (Tankbus) can not be grounded.
Grounding one of the signal wires may shut down the entire fieldbus segment.
Shield Wire Ground
To protect the fieldbus segment (Tankbus) 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.
The Raptor devices are designed for “daisy-chain” connection of shield wiring
in order to enable a continuous shield throughout the Tankbus network.
3.4.5 Cable Selection
for the Tankbus
Use shielded twisted pair wiring for the Rosemount 2410 Series in order to
comply with FISCO
(1)
requirements and EMC regulations. The preferred cable
is referred to as type “A” fieldbus cable. The cables must be suitable for the
supply voltage and 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 1.0 mm
2
or 18 AWG in order to facilitate wiring.
However, cables within the range 0.5 to 1.5 mm
2
or 20 to 16 AWG can be
used.
The FISCO F
OUNDATION™ fieldbus specification requires that cables for the
Tankbus comply with the following parameters:
Table 3-1. FISCO cable
parameters
(1) See IEC 61158-2 and IEC/TS 60079-27:2002.
Parameter
(1)
(1) For further information see requirements of the IEC 61158-2 standard, and safety requirements in
IEC/TS 60079-27:2002.
Value
Loop resistance 15 to 150 /km
Loop inductance 0.4 to 1 mH/km
Capacitance 45 to 200 nF/km
Maximum length of each spur
(2)
cable
(2) A spur is an unterminated part of the network.
60 m in apparatus class IIC and IIB
Maximum length of each trunk
(3)
cable
(3) A trunk is the longest cable path between two devices on the fieldbus network, and is the part of the
network which has terminations at both ends. In the Raptor system, a trunk is typically located
between the 2410 Tank Hub and a splitter or the last device in a daisy-chain configuration.
1000 m in apparatus class IIC and 1900 m in
apparatus class IIB