ABB AC500 PLC Hardware Manual page 1292

System Assembly, Construction and Connection
AC500 (Standard) > Connection and Wiring
Pin
8
9
Bus Cable
Parameter
Type
Characteristic impedance
Cable capacity
Conductor diameter of the cores
Conductor cross section of the cores
Cable resistance per core
Loop resistance (resistance of two cores)
Cable Lengths The maximum possible cable length of a PROFIBUS subnet within a segment depends on the
baud rate (transmission rate).
Baud Rate
9.6 / 19.2 / 93.75 kBaud
187.5 kBaud
500 kBaud
1.5 MBaud
3 MBaud to 12 MBaud
Branch lines are generally permissible for baud rates of up to 1500 kbit/s. But in fact they should
be avoided for transmission rates higher than 500 kbit/s.
Bus Terminating The line ends (of the bus segments) have to be terminated using bus terminating resistors
Resistors according to the drawing below. The bus terminating resistors are usually placed inside the bus
connector.
Repeaters One bus segment can have up to 32 subscribers. Using repeaters a system can be expanded to
up to 126 subscribers. Repeaters are also required for longer transfer lines. Please note that a
repeater's load to the bus segment is the same as the load of a normal bus subscriber. The sum
of normal bus subscribers and repeaters in one bus segment must not exceed 32.
1292
Signal
RxD/TxD-N
CNTR-N
Value
Twisted pair (shielded)
135 Ω...165 Ω
< 30 pF/m
≥ 0.64 mm
≥ 0.34 mm²
≤ 55 Ω/km
≤ 110 Ω/km
Maximum Cable Length
1200 m
1000 m
400 m
200 m
100 m
VP (+5 V)
Data Line B RxD/TxD-P
Data Line A RxD/TxD-N
GND (0 V)
3ADR010121, 13, en_US
Description
Reception / transmission line,
negative
Control signal for repeater,
negative (optional)
6
390 Ohms
3
220 Ohms
8
390 Ohms
5
2019/04/17