Technical data

3.3.2.3 Distributed I/Os (DP)
Data transmission using L2-DP (distributed I/Os) provides a standardized
interface for communication between SIMATIC S5 PLCs and field devices
(DP slave), with the PROFIBUS DP protocol complying with DIN E19245
Part 3.
Data transmission with DP is simple to implement.
The programming and handling is reduced to a minimum for the user. When
using the DP service, part of the I/O area of the PLC is occupied by the
connected DP slaves. The CP 5430 TF/CP 5431 FMS structures the I/O
bytes used in the direction of the CPU.
This means that access by the user program to the I/O bytes used by
L2-DP is acknowledged by the CP 5430 TF/CP 5431 FMS.
Using the L2-DP protocol, the CP 5430 TF/CP 5431 FMS exchanges the
input and output data assigned to the individual DP slaves cyclically.
The basic sequence of this communication is described in Chapter 11.
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Fundamentals of the Model B8976060/02
Volume 1 3 - 18