Endress+Hauser Prosonic S FMU95, Руководство по эксплуатации

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Wiring Prosonic S FMU95
20 E Hauser
4.3 Connection to a PROFIBIS DP network
!
Note!
Information on the structure of a PROFIBUS DP network can be found in the Operating Instructions
BA 034S ("PROFIBUS PA/DP - Guidelines for planning and commissioning".
4.3.1 Cable specifications
For transmission rates up to 12 MBit/s cable type A according to EN 50170 can be used. The
specifications are summarized in the following table:
Pre-assembled cables are available from Hauser (

ä
88, "Accessories").
4.3.2 T-box
It is recommended to connect the Prosonic S to the bus by a T-box.
Suitable T-boxes are available from Hauser (

ä
88, "Accessories").
4.3.3 Spurs
Spurs are the connection cables from the bus to the instrument.
"
Caution!
Obeserve the following:
• Total length of all spurs < 6.6 m (22 ft), (for a maximum baudrate of 1.5 MBit/s)
• For baud rates > 1.5 MBit/s no spurs should be used. A spur is the cable between the connector
and the bus driver in the field instrument. Plant experience has shown that much care should be
taken when planning the spurs. It can not be guaranteed that the sum of all spurs at 1.5 MBit/s
may be 6.6 m (22 ft). The actual arrangement of the field intruments has a great influence on this.
Therefore it is strictly recommended to use no spurs for transmission rates > 1.5 MBit/s.
• If usage of spurs can not be avoided, these may not have a bus bus termination.
Terminator 135

to 165

at a measuring frequency from 3 MHz to 20 MHz
Cable capacitance < 30pF per meter
Core cross-section > 0.34 mm
2
, corresponds to AWG 22
Cable type twisted pairs, 1x2, 2x2 or 1x4 core
Loop resistance 110

per km
Siganl attenuation max. 9 dB over the entire length of the segment
Screening woven copper sheath or woven sheath and foil sheath