FD67 Profibus-DP Manual
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9 Glossary
9.1 General information about the Profibus
Bus segment
The electrical specification of the RS-485 interface limits the number of
users on an RS485 network to 32. If more than 32 Profibus users are to
be used, then the network must be subdivided into segments by using
repeaters.
DP
Distributed Periphery. Profibus protocol for high-speed cyclical data
exchange.
Freeze Mode
The Input data of the slave are "frozen“.
GAP factor
The number of bus cycles after which a DP master searches for new
active subscribers for inclusion in the token ring. This factor can be
modified to optimize the speed of a DP network.
GAP range
The address range in which an active user searches for a new active
user. This range is always between the own address and the address of
the next active user already in the Token Ring. The range from the
highest address up to 127 does not belong to the GAP range.
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. More than one device can have the same ID
number, provided that the numbers can be written to a common GSD file.
This number is allocated by Profibus Nutzerorganisation e.V (Profibus
user organization).
IEC
61158
Globally recognized standard for Profibus DP and FMS which
supersedes the international standard EN 50 170 Volume 2.
Master Class 1
The master which carries out user data transfers.
Master Class 2
Master for control/startup and configuration tasks.
Byte
Term used in IEC 61158. Equivalent to 1 byte or 8 bits.
IDM
Input Data Map
ODM
Output Data Map
PNO
P
rofibus
N
utzer
o
rganisation e.V. (Profibus user organisation)
Repeater
Coupling element for signal conditioning between Profibus segments.
PLC
Programmable Logic Controller
Sync-Mode
The output data of the Slave are "frozen“.