Manual

PROFIBUS Network Interface
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EIO0000000046 04/2013
4.2 General Principles
About the PROFIBUS Network
PROFIBUS and PROFIBUS-DP
 PROFIBUS is an open and independent communication standard adapted to
industrial applications.
 PROFIBUS-DP (Process Fieldbus Decentralized Peripheral) is the PROFIBUS
version optimized for high speed data transmission within a decentralized I/O
architecture.
Role
 PROFIBUS enables devices from different manufacturers to communicate
without needing a specific interface.
 PROFIBUS-DP is particularly adapted to applications for which the response time
is a critical factor.
Master/Slave Communication
Compatibility between the physical equipment installed and the configuration
expected by the application is controlled during master and slave communication
establishment. The master sends the slave configuration and settings data as soon
as it recognizes the equipment installed. The slave provides diagnostic information
to the master about its operating state.
The physical link is a type A shielded twisted pair.
The data exchange between the Master (the processing unit) and the Slaves
(decentralized devices) is carried out on a cyclical basis: the master sends the
output data to the slaves, which respond with their input data.
Slaves and Repeaters
32 slaves in total can be connected to a bus segment. To increase the number of
slaves, repeaters must be added to create new bus segments.
Repeaters are also used to physically isolated bus segments. In total, the number of
slaves must not be greater than 126.
There must be a line terminator on the bus at the ends of each new segment.