PROline Prosonic Flow 93 PROFIBUS-DP/-PA 4 Wiring
Endress+Hauser 41
4Wiring
#
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 E+H sales office if you have any questions.
4.1 Cable specifications for PROFIBUS
4.1.1 PROFIBUS-DP cable specifications
Two types of cable are specified for the bus line in the EN 50 170 standard. Cable type
A can be used for all transmission rates up to 12 Mbit/s. The cable parameters can be
taken from the following table:
When setting up the bus, observe the following points:
The maximum line length (segment length) of a PROFIBUS-DP system depends on
the transmission rate. With PROFIBUS-RS 485 cable type A, this value is:
A maximum of 32 stations are permitted per segment.
Each segment is terminated at both ends with a terminating resistor.
The bus length or number of users can be increased by installing a repeater.
The first and last segments can support a max. of 31 devices. The segment between
repeaters can support a max. of 30 stations.
The maximum distance achievable between two bus users is calculated as:
(NUM_REP + 1) x segment length
NUM_REP = maximum number of repeaters, which can be placed in series,
depending on the respective repeater.
Example:
According to the manufacturer's information, a maximum of 9 repeaters may be
placed in series on a standard segment.
The maximum distance between two bus users at a transmission rate of 1.5 MBit/s is
calculated as: (9 + 1) x 200 m = 2000 m
Cable type A
Characteristic
impedance
135... 165
at a measurement frequency of 3...20 MHz
Cable capacitance <30 pF/m
Wire size >0.34 mm
2
, equals AWG 22
Cable type Twisted pairs, 1 x 2, 2 x 2 or 1 x 4 conductors
Loop resistance 110
/km
Signal attenuation Max. 9 dB over the entire length of the line segment
Shielding Copper braided shield or braided shield and foil screen
Transmission rate [kBit/s] 9,6...93,75 187,5 500 1500 300...12000
Cable length [m] 1200 1000 400 200 100
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