Profibus Dp (Process Field Bus - Decentral Periphery) - ABB AC500 Introduction Manual

Brief information about PROFIBUS DP

PROFIBUS DP (Process Field Bus - Decentral Periphery)

PROFIBUS DP is an open, high-speed and widely-used field bus. It provides multi-master and master-
slave communication in the field area. This field bus can accordingly be used for AC500 and AC31
control system series and for field-bus-neutral FBP devices (decentralized I/Os and intelligent switching
devices) via the PROFIBUS-FBP connector.
Communication
The masters rule data traffic on the bus. When in possession of the bus access authorization (token), the
masters can transmit data without an external request. The passive devices, known as slaves, do not
receive any bus access rights; they acknowledge messages received, or respond to a query from a
master. Baud rates from 9.6 kBaud to 12 MBaud are supported. A maximum of 126 devices can be
operated on the bus.
Data exchange
This is handled predominantly in cyclical mode be-tween master and slave. The requisite communication
functions have been specified by the PROFIBUS DP basic functions in accordance with EN 50170. Each
master has full write and read access to its assigned slaves, but only read access to the slaves assigned
to other bus masters. There is no direct data exchange between masters. Acyclical services (DP-V1) for
parameterization and diagnostics between master and slave are also available. This is performed in
parallel to the master's cyclical user data traffic.
PROFIBUS DP – the functionality at a glance
• Max. 126 subscribers via amplifier and max. 32 subscribers (master/slaves) per bus segment
• Data transmission rate from max. 12 MBit/s with a cable length of 100 m, up to 93.75 kBit/s with 1200 m
• Multi-master or master/slave communication. Bus access of the masters using token
• Connection of the master CPU and the associated communication module via a 9-pole SUB-D plug
connector. Connection of slaves (CPU, I/Os and intelligent switching devices) via FieldBusPlug
• The system cable is a shielded twisted-pair line or a fiber-optic cable; transmission standard EIA RS485
Diagnostics
Detailed diagnostic messages for rapid trouble-shooting are shown on the CPU display or can be called
using the programming tool. In addition, the device status is indicated at the communica-tion module by
four LEDs.
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G1
Introduction to AC500 1-14
AC500 / Issued: 07.2006