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Electrical connection
34
7.1.3
Terminal assignment
Transmitter: supply voltage, input/outputs
The terminal assignment of the inputs and outputs depends on the individual order
version of the device. The device-specific terminal assignment is documented on an
adhesive label in the terminal cover.
Supply voltage
1 (+)
2 (–)
Terminal assignment of the remote display and operating module → 39.
7.1.4
Shielding and grounding
Optimum electromagnetic compatibility (EMC) of the fieldbus system can only be
guaranteed if the system components and, in particular, the lines are shielded and the
shield forms as complete a cover as possible. A shield coverage of 90% is ideal.
• To ensure an optimum EMC protective effect, connect the shield as often as possible to
the reference ground.
• For reasons of explosion protection, you should refrain from grounding however.
To comply with both requirements, the fieldbus system allows three different types of
shielding:
• Shielding at both ends.
• Shielding at one end on the feed side with capacitance termination at the field device.
• Shielding at one end on the feed side.
Experience shows that the best results with regard to EMC are achieved in most cases in
installations with one-sided shielding on the feed side (without capacitance termination at
the field device). Appropriate measures with regard to input wiring must be taken to allow
unrestricted operation when EMC interference is present. These measures have been
taken into account for this device. Operation in the event of disturbance variables as per
NAMUR NE21 is thus guaranteed.
Where applicable, national installation regulations and guidelines must be observed
during the installation!
Where there are large differences in potential between the individual grounding points,
only one point of the shielding is connected directly with the reference ground. In systems
without potential equalization, therefore, cable shielding of fieldbus systems should only
be grounded on one side, for example at the fieldbus supply unit or at safety barriers.
NOTICE
In systems without potential matching, the multiple grounding of the cable shield
causes mains frequency equalizing currents!
Damage to the bus cable shield.
‣
Only ground the bus cable shield to either the local ground or the protective ground at
one end. Insulate the shield that is not connected.
Input/output 1
Input/output 2
26 (B)
27 (A)
24 (+)
Device-specific terminal assignment: adhesive label in terminal cover.
Proline Promass I 300 PROFIBUS DP
Input/output 3
25 (–)
22 (+)
Endress+Hauser
23 (–)
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