Endress+Hauser Proline Prosonic Flow 93, Руководство по эксплуатации

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Proline Prosonic Flow 93 PROFIBUS DP/PA Wiring
Hauser 59
Example
In accordance with manufacturer specifications, 9 repeaters can be switched in series when using
a standard line. The maximum distance between two bus users at a transmission rate of
1.5 MBit/s can be calculated as follows:
(9 + 1) x 200 m (660 ft) = 2 000 m (6600 ft).
Spurs
Note the following points:
• Length of spurs < 6.6 m (21.7 ft) (at max.1.5 MBit/s)
• No spurs should be used for transmission rates >1.5 MBit/s.
The line between the connector and the bus driver is described as a spur. Experience has shown
that you should proceed with caution when configuring spurs. For this reason, you cannot
presume that the sum of all spurs at 1.5 MBit/s may be 6.6 m (21.7 ft).
This is affected greatly by the arrangement of the field devices. Therefore, we recommend you do
not use any spurs, if possible, at transmission rates >1.5 MBit/s.
• If you cannot avoid using spurs, then they may not include any bus terminators.
Bus termination
It is important to terminate the RS485 line correctly at the start and end of the bus segment since
impedance mismatch results in reflections on the line which can cause faulty communication
transmission
→
ä
86.
Further information
General information and further notes regarding the wiring are contained in BA034S/04:
"Guidelines for planning and commissioning, PROFIBUS DP/PA, field communication."