Wiring
Proline Promag 55 FOUNDATION Fieldbus
36
Hauser
4
Wiring
#
Warning!
• When connecting Ex-certified devices, please take note of the instructions and wiring diagrams
in the Ex-specific supplement to these Operating Instructions. Should you have any questions,
please contact your Hauser sales office for assistance.
• When installing remote versions, please make sure that the serial number on the sensor and the
serial number on the transmitter are
identical
. Measuring errors can occur if this is not adhered to.
!
Note!
The device does not have an internal circuit breaker. An external switch or circuit breaker must
therefore be installed which can be used to disconnect the device from the main power source.
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.
In accordance with IEC 61158-2 (MBP), four different cable types (A, B, C, D) can be used with
the FOUNDATION Fieldbus 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 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. However, they determine important
characteristics of the design of the fieldbus, such as distances bridged, number of users,
electromagnetic compatibility, etc.
Type A
Type B
Cable structure
Twisted pair, shielded
One or more twisted pairs, fully
shielded
Wire cross-section
0.8 mm² (AWG 18)
0.32 mm² (AWG 22)
Loop-resistance (DC)
44
Ω
/km
112
Ω
/km
Characteristic impedance
at 31.25 kHz
100
Ω
± 20%
100
Ω
± 30%
Attenuation constant at 39 kHz
3 dB/km
5 dB/km
Capacitive asymmetry
2 nF/km
2 nF/km
Envelope delay distortion
(7.9 to 39 kHz)
1.7
μ
s/km
*
Shield coverage
90%
*
Max. cable length (incl. spurs >1 m)
1900 m (6233 ft)
1200 m (3937 ft)
* Not specified