Wiring; Profibus Cable Specifications; Profibus Dp Cable Specification - Endress+Hauser PROFI BUS Proline Promag 53 PROFIBUS DP Operating Manual

Proline Promag 53 PROFIBUS DP/PA
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Endress+Hauser
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Wiring

Warning!
• When connecting Ex-certified devices, see the notes and diagrams in the Ex-specific supplement
to this Operating Manual. Please do not hesitate to contact your Endress+Hauser sales office if
you have any questions.
• If you use remote versions, connect sensors only to transmitters that have the same serial number.
Measuring errors can occur if the devices are not connected in this way.
4.1

PROFIBUS cable specifications

4.1.1

PROFIBUS DP cable specification

Cable type
Two versions of the bus line are specified in IEC 61158. Cable type A can be used for all
transmission rates up to 12 Mbit/s. Please refer to the table for the cable parameters:
Cable type A
135 to 165 Ω at a measuring frequency of 3 to 20 MHz
Characteristic impedance
Cable capacitance < 30 pF/m
Core cross-section >0.34 mm
Cable type Twisted in pairs, 1 x 2, 2 x 2 or 1 x 4 wire
110 Ω/km
Loop-resistance
Signal damping Max. 9 dB over the entire length of the cable section
Shielding Copper braided shielding or braided shielding and foil shielding
Bus structure
Note the following points:
• The maximum line length (segment length) depends on the transmission rate.
For cable type A, the maximum line length (segment length) is as follows:
Transmission rate [kBit/s]
Line length [m]
• A maximum of 32 users are permitted per segment.
• Each segment is terminated at either end with a terminating resistor.
• The bus length or the number of users can be increased by introducing a repeater.
• The first and last segment can comprise max. 31 devices.
The segments between the repeaters can comprise max. 30 stations.
• The maximum distance between two bus users can be calculated as follows: (NO_REP + 1) x
segment length
!
Note!
NO_REP = maximum number of repeaters that may be switched in series depending on the
repeater in question.
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 = 2000 m
2
, corresponds to AWG 22
9.6 to 93.75 187.5
1200 1000
500 1500 300 to 12000
400 200
Wiring
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