Wiring Levelflex M FMP40 FOUNDATION Fieldbus
38 Endress+Hauser
4.2.7 Overvoltage protection
If the measuring device is used for the level measurement in flammable liquids which requires the
use of an overvoltage protection according to EN/IEC 60079-14 or EN/IEC 60060-1
(10 kA, Puls 8/20 μs) it has to be ensured that
• the measuring device with integrated overvoltage protection with gas discharge tubes within the
T12-enclosure is used, refer to "Ordering structure", → ä 6
or
• this protection is achieved by the use of other appropriate measures (external protection devices
e.g. HAW562Z).
4.3 Recommended connection
For maximum EMC protection please observe the following points:
• The external ground terminal on the transmitter must be connected to ground.
• The continuity of the cable screening between tapping points must be ensured.
• If potential equalisation is present between the individual grounding points, ground the screening
at each cable end or connect it to the device housing (as short as possible).
• If there are large differences in potential between grounding points, the grounding should run via
a capacitor that is suitable for high frequency use (e.g. ceramic 10 nF/250 V&).
"
Caution!
Applications, which are subject to the explosion prevention, permit only under special conditions
the repeated grounding of the protective screen, see to EN 60079-14.
4.4 Degree of protection
• with closed housing tested according to
– IP68, NEMA6P (24 h at 1.83 m under water surface)
– IP66, NEMA4X
• with open housing: IP20, NEMA1 (also ingress protection of the display)
4.5 Post-connection check
After wiring the measuring device, perform the following checks:
• Is the terminal allocation correct (→ ä 34, 35)?
• Is the cable gland tight?
• Is the Foundation Fieldbus connector screwed tight?
• Is the housing cover screwed tight?
• If auxiliary power is available:
Is the device ready for operation and is the liquid crystal display visible?
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