Wiring; Foundation Fieldbus Cable Specification; Cable Type - Endress+Hauser Proline Prosonic Flow 93 Operating Instructions Manual

Wiring

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58
4 Wiring
Warning!
When connecting Ex-certified devices, please refer to the notes and diagrams in the Ex-specific
supplement to these Operating Instructions.
Please do not hesitate to contact your Endress+Hauser sales office if you have any questions.
Note!
The device does not have an internal power switch. For this reason, assign the device a switch or
power-circuit breaker which can be used to disconnect the power supply line from the power grid.
4.1

FOUNDATION Fieldbus cable specification

4.1.1

Cable type

Twin-core cable is recommended for connecting the flowmeter to the FOUNDATION Fieldbus H1.
Following IEC 61158-2 (MBP), four different cable types (A, B, C, D) can be used with the
FOUNDATION Fieldbus, 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 interference and thus the
most reliable data transfer. With cable type B more than one fieldbus (with the same degree of
protection) may be operated in a 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 important
characteristics of the design of the fieldbus, such as distances bridged, number of users,
electromagnetic compatibility, etc.
Cable structure
Wire cross-section
Loop-resistance (DC)
Characteristic impedance
at 31.25 kHz
Attenuation constant at 39 kHz
Capacitive asymmetry
Envelope delay distortion
(7.9 to 39 kHz)
Shield coverage
Max. cable length (incl. spurs >1 m)
* Not specified
Proline Prosonic Flow 93 FOUNDATION Fieldbus
Type A
twisted pair, shielded
2
0.8 mm (AWG 18)
44 /km
100  ± 20%
3 dB/km
2 nF/km
1.7 s/km
90%
1900 m (6233 ft)
Type B
One or more twisted pairs,
fully shielded
2
0.32 mm (AWG 22)
112 /km
100  ± 30%
5 dB/km
2 nF/km
*
*
1200 m (3937 ft)
Endress+Hauser