Festo CTEU-PB - Fieldbus Baud Rate and Fieldbus Length

1. Installation
1-14
Festo P.BE-CTEU-PB-OP+MAINT-EN en 1208NH English
Surge impedance: 135 ... 165 ohms (3 ... 20 MHz)
Capacity per unit length: < 30 nF/km
L oop resistance: < 110 ohms/km
Wire diameter: > 0.64 mm
Wire cross section: › 0.34 mm
2
Fieldbus segment length Precise specifications on the fieldbus segment length can be
found in chap. 1.5.3 and in the product documentation of
your control system.
1.5.3 Fieldbus baud rate and fieldbus length
Note
The maximum permissible fieldbus segment lengths (cable
length without repeater) are dependent on the baud rate
used.
• Observe the maximum permissible segment length if
you connect the bus node to a fieldbus segment.
• Avoid branch lines.
The baud rate is specified by the master. It limits the usable
cable lengths (see Tab. 1/2).
Cable length (approximate values) dependent on the data rate (baud rate)
Baud rate
1)
Segment length
2)
Branch line length
3)
(total)
9.6 kBaud Max. 1200 m Max. 500 m
19.2 kBaud Max. 1200 m Max. 500 m
93.75 kBaud Max. 1200 m Max. 100 m
187.5 kBaud Max. 1000 m Max. 33.3 m
500 kBaud Max. 400 m Max. 20 m