Screening And Potential Equalisation; Degree Of Protection; Connection Check - Endress+Hauser iTEMP HART TMT142 Manuel De Mise En Service

TMT142
Endress+Hauser
4.4

Screening and potential equalisation

Please take note when installing the device:
If screened (shielded) cables are used then the screen connected to the output (output signal 4 to
20mA) must be at the same potential as the screen at the sensor connection!
When operating in plants with high electromagnetic fields, it is recommended that all cables be
screened using a low ohm ground connection. Due to the possible danger of lightning strikes
screening is also recommended for cables that are run outside buildings!
4.5

Degree of protection

The device conforms to the requirements to IP 67 ingress protection. In order to fulfil an IP 67
degree of protection after installation or service, the following points must be taken into
consideration:
• The housing seals must be clean and undamaged before they are replaced into the sealing rebate.
If they are found to be too dry then they should be cleaned or even replaced.
• All housing screws and covers must be pulled tight.
• The cables used for connection must be of the correct specified outside diameter (e.g. M20 x 1.5,
cable diameter from 8 to 12 mm; 0.315 to 0.47 in).
• Tighten cable gland (→ Fig. 8).
• Loop the cable before placing into the cable entry ("Water sack", → Fig. 8). This means that any
moisture that may form cannot enter the gland. Install the device so that the cable entries are not
facing upwards.
• Cable entries not used are to be blanked off using the blanking plates provided.
• The protective olive must not be removed from the cable gland.
Fig. 8: Connection hints to retain IP 67 protection
4.6

Connection check

After the electrical installation of the device, always perform the following final checks:
Device condition and specification
Are the device or the cables damaged (visual check)?
Electrical connection
Is the cable installation correctly separated, with no loops or crossovers?
Are the cables load relieved?
Have the cables been correctly connected? Compare with the
connection schematic on the terminals or → Fig. 5.
Are all terminal screws tightened?
Is the cable entry sealed?
Is the housing cover screwed tight?
Wiring
Hint
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Hint
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See connection schematic on the
housing
Visual check
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