Product Overview; What Are Distributed I/O Devices; What Is Profibus Dp - Siemens SIMATIC ET 200PA SMART Operating Instructions Manual

Product overview

1.1

What Are Distributed I/O Devices

Area of application
When a system is set up, it is common for the inputs to and outputs from the process to be
incorporated centrally in the automation system.
When the inputs and outputs are located at large distances from the automation system, the
wiring may become very extensive and confusing. Electromagnetic interference may impair
reliability.
Distributed I/O devices are the ideal solution for such systems:
● The control CPU is located at a central location.
● The I/O devices (inputs and outputs) operate locally at their distributed locations.
● The powerful PROFIBUS DP with fast data transmission speeds ensures that the control
CPU and the I/O devices communicate smoothly.
1.2

What is PROFIBUS DP?

What is PROFIBUS DP?
PROFIBUS DP is an open bus system according to IEC 61784‑1:2002 Ed1 CP 3/1 with the
"DP" transmission protocol. DP stands for distributed peripherals.
Physically, the PROFIBUS DP is either an electric network based on a shielded two-wire line
(RS 485) or an optical network based on a fiber-optic cable (FOC).
The transmission protocol "DP enables a fast, cyclic data exchange between the control CPU
and the distributed I/Os.
What are the DP master and DP slaves?
The DP master is the connecting link between the control CPU and the distributed I/Os. The
DP master exchanges the data via the PROFIBUS DP with the distributed I/Os and monitors
the PROFIBUS DP.
The distributed I/Os (= DP slaves) prepare the data of the encoder and the actuators on site in
such a way that they can be transmitted via the PROFIBUS DP to the control CPU.
ET 200PA SMART
Operating Instructions, 06/2019, A5E34192013-AB
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