ABB FEX300, Инструкция по эксплуатации

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Mounting
OI/FEX300/FEX500-EN FEX300, FEX500 33
4.7 Ground
Important (Notice)
An additional document with Ex safety instructions is available for measuring systems that are
used in explosion hazardous areas. As a result, it is crucial that the specifications and data it
lists are also observed.
4.7.1 General information on ground connections
Observe the following items when grounding the device:
• For plastic pipes or pipes with insulating lining, the ground is provided by the grounding plate
or grounding electrodes.
• When stray potentials are present, install a grounding plate upstream and downstream of the
flowmeter sensor.
• For measurement-related reasons, the potentials in the station ground and in the pipeline
should be identical.
• An additional ground on the terminals is not required.
Important (Notice)
If the flowmeter sensor is installed in plastic or earthenware pipelines, or in pipelines with an
insulating lining, transient current may flow through the grounding electrode in special cases.
In the long term, this may destroy the sensor, since the ground electrode will in turn degrade
electrochemically. In these special cases, the connection to the ground must be performed
using grounding plates. Install a grounding plate upstream and downstream of the device in
this case.
4.7.2 Metal pipe with fixed flanges
Use a copper wire (at least 2.5 mm² (14 AWG)) to establish the ground connection between the
sensor (1), the pipeline flanges and an appropriate grounding point.
Flange design Wafer flange design
Fig. 25: Metal pipe, without liner