Lenze · E84AYCPM communication module (PROFIBUS®) · Communication Manual · DMS 5.0 EN · 11/2012 · TD17 28
5 Installation
5.3 Activating the bus terminating resistor
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5.3.1 Bus cable specification
Bus cable length
The length of the bus cable depends on the baud rate and cable type used. The data in the following
table applies to PROFIBUS cables of "FC-Standard Cable" cable type .
Tip!
We recommend taking the use of optical fibres into consideration for high baud rates.
Advantages of optical fibres:
• External electromagnetic interferences have no effect on the transmission path.
• Bus lengths of several kilometres are also possible with higher baud rates.
• The bus length is ...
• independent of the baud rate;
• dependent on the optical fibre used.
Note!
Only use cables which meet the listed specifications of the PROFIBUS user organisation.
Area Values
Cable resistance 135 ... 165 Ω/km, (f = 3 ... 20 MHz)
Capacitance per unit length ≤ 30 nF/km
Loop resistance < 110 Ω/km
Core diameter > 0.64 mm
Core cross-section > 0.34 mm
2
Cores Twisted in pairs, insulated and shielded
Baud rate Length
9.6 ... 93.75 kbps 1200 m
187.5 kbps 1000 m
500 kbps 400 m
1500 kbps 200 m
3000 ... 12000 kbps 100 m
Note!
The baud rate depending of the data volume, cycle time and number of stations should
only be selected as high as required for the application.
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