Em Dp01 Profibus Dp Module; Distributed Peripheral (Dp) Standard Communications - Siemens SIMATIC S7 System Manual

8.5.1

EM DP01 PROFIBUS DP module

8.5.1.1

Distributed Peripheral (DP) standard communications

PROFIBUS DP (or DP Standard) is a remote I/O communications protocol defined by the
European Standard EN 50170. Devices that adhere to this standard are compatible even
though they are manufactured by different companies. DP stands for distributed peripherals,
that is, remote I/O. PROFIBUS stands for Process Field Bus.
The EM DP01 PROFIBUS DP module has implemented the DP Standard protocol as
defined for DP devices in the following communications protocol standards:
● EN 50 170 (PROFIBUS) describes the bus access and transfer protocol and specifies the
properties of the data transfer medium.
● EN 50 170 (DP Standard) describes the high-speed cyclic exchange of data between
DP masters and DP devices. This standard defines the procedures for configuration and
parameter assignment, explains how cyclic data exchange with distributed I/O functions,
and lists the diagnostic options which are supported.
A DP master is configured to know the addresses, DP device types, and any parameter
assignment information that the DP devices require. The DP master is also told where to
place data that is read from the DP devices (inputs) and where to get the data to write to the
DP devices (outputs). The DP master establishes the network and then initializes its
DP devices. The DP master writes the parameter assignment information and I/O
configuration to the DP device. The DP master then reads the diagnostics from the
DP device to verify that the DP device accepted the parameters and the I/O configuration.
The DP master then begins to exchange I/O data with the DP device. Each transaction with
the DP device writes outputs and reads inputs. The data exchange mode continues
indefinitely. The DP devices can notify the DP master if there is an exception condition, and
the DP master then reads the diagnostic information from the DP device.
Once a DP master has written the parameters and I/O configuration to a DP device, and the
DP device has accepted the parameters and configuration from the DP master, the
DP master owns that DP device. The DP device only accepts write requests from the
DP master that owns it. Other DP masters on the network can read the DP device's inputs
and outputs, but they cannot write anything to the DP device.
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
Communication
8.5 PROFIBUS
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