Electrical installation – Lenze 931K User Manual
Page 13
Electrical installation
Wiring
l
13
KHB 13.0004−EN 2.1
Baud rates
Baud rate [kbps]
Length of the transmission cable [m]
9.6 ... 93.75
1200
187.5
1000
500
400
1500
200
3000
100
6000
100
12000
100
)
Note!
ƒ
The baud rate depends on the data volume, cycle time and number of bus
stations.
ƒ
The baud rate selected should be as low as possible. The lower the baud
rate, the more insensitive the PROFIBUS is to parasitic coupling.
I
Tip!
For high baud rates, we recommend to consider the application of optical
fibres.
Advantages of optical fibres:
ƒ
External electromagnetic interferences have no effects on the transmission
path.
ƒ
Bus lengths of several kilometres are also possible with higher baud rates.
The bus length is
– independent of the baud rate.
– depend on the optical fibre used.
Specification of the transmission cable
Please follow the specifications of the PROFIBUS user organisation (PUO) for signal cables:
Bus cable specification
Specific resistance
135 − 165
W/km, (f = 3 − 20 MHz)
Capacitance per unit length
£ 30 nF/km
Loop resistance
< 110
W/km
Core diameter
> 0.64 mm
Core cross−section
> 0.34 mm
2
Cores
Double twisted, insulated and shielded