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PROline Promass 80 PROFIBUS-PA
#
Endress+Hauser
2
Wiring
Warning:
• When connecting Ex-certified devices, see the notes and diagrams in the Ex-specific
supplement to these Operating Instructions. Please do not hesitate to contact your
E+H representative if you have any questions.
• For the remote version, always make sure that you connect the sensor only to the
transmitter having the same serial number. Communication errors can occur if the
devices are not connected in this way.
2.1
Cable specifications for PROFIBUS-PA
Cable type
Twin-core cables are required for connecting the device to the fieldbus. By analogy with
IEC 61158-2 protocol four different cable types (A, B, C, D) can be used with the field-
bus protocol, only two of which (cable types A and B) are shielded.
• Cable types A or B are particularly preferable for new installations. Only these types
have cable shielding that guarantees adequate protection from electromagnetic inter-
ference and thus the most reliable data transfer. On multi-pair cables (type B), it is per-
missible to operate multiple fieldbuses (with the same degree of protection) on one
cable. No other circuits are permissible in the same cable.
• Practical experience has shown that cable types C and D should not be used due to
the lack of shielding, since the freedom from interference generally does not meet the
requirements described in the standard.
The electrical data of the fieldbus cable have not been specified but determine impor-
tant characteristics of the design of the fieldbus, such as distances bridged, number of
users, electromagnetic compatibility, etc.
Cable structure
Wire size
Loop resistance (DC)
Impedance at 31.25 kHz
Attenuation at 39 kHz
Capacitive asymmetry
Envelope delay distortion
(7.9 through 39 kHz)
Shield coverage
Max. cable length
(inc. spurs >1 m)
* not specified
Cable type A
twisted pair,
shielded
2
0.8 mm
(AWG 18)
44 Ω /km
100 Ω ± 20%
3 dB/km
2 nF/km
1.7 µ s/km
90%
1900 m
2 Wiring
Cable type B
one or more twisted pairs,
fully shielded
2
0.32 mm
(AWG 22)
112 Ω /km
100 Ω ± 30%
5 dB/km
2 nF/km
*
*
1200 m
7
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