ABB AC 800M, User Manual

Page: 102 / 118

Active network terminator and repeater Section 4 Commissioning of PROFIBUS equipment
102 3BDS009029R5001 B
Active network terminator and repeater
The active network components described below can be used to construct simple or
complex PROFIBUS networks, and either electrical cables or optical fibre cables
can be used as the transmission medium. Since most active components have IP20
protection, it will usually need a cabinet, a wall mounted cubicle or a comparable
packing to protect the components. A DIN mounting rail is adequate for attachment.
It may implement an external active bus terminator by means of a special bus
terminator or a repeater. The external bus terminator relieves the bus subscriber
from supplying the resistor network. Now the redundant master or the last
subscriber on this transmission line can be switched idle without loss of
communication.
Depending on the type, the module can be fed with 24 VDC or 230 VAC. The
resistor network (terminator) is not placed in the module itself, but in the
PROFIBUS connector.
RS 485 Repeater
There are component under the type description "Repeater RS 485" available, that
can be used to connect two electrical PROFIBUS segments with a maximum of 32
stations each. Nine repeaters can be included in a line. This makes it possible to
Network devices cause a N x bit time delay of data telegrams. The delay times are
device specific and depend upon the selected transmission rate. They must be
taken into consideration in the bus configuration manually.
Figure 36. Active PROFIBUS Terminator from Kuhnke and Siemens