Installation
Electrical installation
Wiring with a host (master)
5
l
25
EDSMF2133IB EN 5.0
Number of bus devices
M
123
SS S S S
RR
2133PFB004
Segment Master (M) Slave (S) Repeater (R)
11
2
31
30
−
−
2 − 30 1
3 − 30 1
I Tip!
Repeaters do not have a device address. When calculating the maximum
number of bus devices, they reduce the number of devices by 1 on each side of
the segment.
Repeaters can be used to build up line and tree topologies. The maximum total
bus system expansion depends on ...
ƒ the baud rate used;
ƒ the number of repeaters used.
Specification of the transmission cable
) Note!
Only use cables complying with the listed specifications of the PROFIBUS user
organisation.
Field Values
Specific resistance 135 ... 165 /km, (f = 3 ... 20 MHz)
Capacitance per unit length 30 nF/km
Loop resistance < 110 /km
Core diameter > 0.64 mm
Core cross−section > 0.34 mm
2
Cores Twisted double, insulated and shielded