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Glossary
General Information About Profibus
Bus segment
The electrical specification of the RS-485 interface limits the number of
users on an RS485 network to 32. If there are more than 32 Profibus
users, divide the network into segments using repeaters.
DP
D
ecentral
P
eriphery, Profibus protocol for rapid cyclical data exchange.
Freeze mode
The Input data of the slave are "frozen".
GAP factor
The number of bus passes after which a DP Master searches for
additional active users to include them in the token ring. This factor can
be modified to optimize the speed of a DP network.
GAP area
The address area in which an active user searches for additional active
users. This area is always between the own address and the address of
the next active user already in the Token Ring. The area from the highest
address up to 127 does not belong to the GAP area.
GSD
The devices master file describes the technical features of a Profibus
product. This file is required to configure a Profibus system, and is
provided by the device's manufacturer.
ID number
A 16-bit number which clearly identifies a Profibus product. It is a
reference to the GSD file. Other devices may have the same ID number,
provided they can be configured in a common GSD file. This number is
allocated by Profibus Nutzerorganisation e.V..
IEC 61158
Globally recognized standard for Profibus DP and FMS Successor of the
international standard EN 50170, Volume 2.
Byte
Term defined by IEC 61158. 1 byte corresponds to 8 bits.
PNO
P
rofibus
N
utzer
o
rganisation e.V (German Profibus user organization).
Repeater
Coupling element for signal conditioning between Profibus segments.
SPC
Stored Program Controller
Sync Mode
The output data of the Slave are "frozen".
Token
The active user (master) in possession of the token can carry out data
exchange with the slaves which it has parameterized and configured. On
completion of the data cycle, the active user passes the token on to the
next active user.
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