Siemens SIMATIC IM 178-4 Manual page 71

PROFIBUS
PROcess FIeld BUS, German process and fieldbus standard as specified in the
PROFIBUS standard (EN 50170). This specifies functional, electrical and
mechanical properties for a bit-serial fieldbus system.
PROFIBUS is a bus system that networks PROFIBUS-compatible programmable
controllers and field devices at the cell and field level. PROFIBUS exists with the
DP (= Distributed Peripheral I/O), FMS (= Fieldbus Message Specification) or TF
(= Technological Functions) protocols.
PROFIBUS address
Each node must be assigned a PROFIBUS address to identify uniquely in
PROFIBUS DP.
PCs/programming devices or the ET 200 handheld device have PROFIBUS
address "0".
DP masters and DP slaves have a PROFIBUS address in the range 1 to 125.
PROFIBUS DP
PROFIBUS bus system with the DP protocol. DP stands for Distributed
Peripheral I/Os. The IM 178-4 is based on the standard EN 50 170, Volume 2,
PROFIBUS.
Programming device
Programming devices (PGs) are basically personal computers designed for use
in industry. They are particularly compact and can be transported. Programming
devices are characterized by a special hardware and software design intended
for use in conjunction with SIMATIC programmable logic controllers.
Reference potential
Potential starting from which the voltages of the circuits involved are referred
and/or measured.
Segment
The LAN cable between two terminating resistors forms a segment. A segment
contains 0 to 32
repeaters.
IM 178-4
C79000-G7076-C178-01
nodes. Segments can be interconnected using RS 485
Glossary
Glossary-5