27
Setting up a PROFIBUS network
Section 2-5
• Setup the PROFIBUS network, see section
2-5 Setting up a PROFIBUS
network
, configure the PROFIBUS master unit using the master configu-
ration tool on the Personal Computer, and download the configuration to
the master unit.
• Refer to the manuals of the connected devices, equipped with either Host
Link or Compoway-F communication, how to set up the network.
2-4-1
Selecting a node address
1,2,3...
1.
Make sure that the power supply is turned OFF before setting the node ad-
dress.
2.
Set the switch to the desired node address. Use a small screwdriver to
make the setting, taking care not to damage the rotary switch. The node
address is factory-set to 0. Make sure that the node address is unique on
the PROFIBUS-DP network, i.e. there must be no other unit with the same
node address.
3.
Turn ON the power supply of the Unit.
2-5
Setting up a PROFIBUS network
2-5-1
Network Structure
Communication Medium
The PROFIBUS standard defines the use of EIA RS-485 as the main commu-
nication transport medium. The PROFIBUS-DP Gateway Unit is designed to
interface directly to this type of medium. This section will discuss the setup of
networks based on this medium.
Note
The other communication medium specified for PROFIBUS is optical fibre.
The PROFIBUS-DP Gateway Unit does not provide a direct interface to this
type of medium. However, by using third party couplers an interface between
EIA RS-485 and optical fibre networks can be made.
Linear Bus Topology
PROFIBUS-DP defines the use of the Linear Bus Network Topology. The Bus
must be terminated at both ends, and must not contain network branches.
The total cable length of the bus depends on the cable and the selected baud
rate. Also, RS-485 specifies a maximum of up to 32 devices - master and
slave devices - per line segment. If more than 32 devices are to be con-
nected, or if the total length of the segment must be extended beyond its max-
imum, repeaters must be used to link the separate segments.
Note
Repeaters are devices which connect two segments. They do not have a
device address of their own, but they do count in the total number of devices
in a segment.
Repeaters
A maximum of up to three repeaters between two devices in a network can be
used, i.e. a network can consist of up to 4 segments. The maximum number
