Profibus Dp; Overview; Command-Oriented Data Exchange - Bosch Rexroth ID 40 Manual

7 Profibus DP

7.1 Overview

The ID 40/SLK-PDP supports the basic functions of the Profibus DP Communication
Profile as per EN 50170.
The SLK does not support any extended DP functions such as noncyclical read and
write functions, as specified for DP-V1.
Data is exchanged through the cyclical data communication of a Class 1 DP master
(DPM1).
Based on this cyclical data communication, the SLK offers two types of data
transmission:
• Command-oriented data exchange, bidirectional data transmission between bus
master and SLK.
• Event-oriented data exchange, unidirectional data transmission from SLK to bus
master
Command- and event-oriented data exchange is mapped to different I/O addresses
in the controller.

7.2 Command-oriented data exchange

Command-oriented data exchange is bidirectional and allows parameters to be set
for event-oriented data exchange, as well as the transmission of data from and to
data carriers/the SLK.
The following functions are supported:
• Writing data (MDT data only in CONNECTED state).
• Reading data
• Configuring unbuffered prefetch
• Configuring buffered prefetch, reading the prefetch buffer
• Configuring pretransmit
A command consists of multiple bytes. The first byte (byte 0) always contains the
command code. The entire command byte sequence is stored on the output map
of the user controller. The SLK receives the command by inverting the toggle bit
(bit 7 in byte 0). The SLK returns the same bit value once the command has been
executed.
3 842 530 344/2014-05, MIT: ID 40, Bosch Rexroth AG
PROOF COPy 1 | 20.05.2014 | FOR INTERNAL USE ONLy
Profibus DP 49/176