PROFIBUS:sup:® DP-V0 <—> PROFIBUS DP-V1

Commands and monitoring signals

The transfer of commands and monitoring signals is the essential task of the field bus and the connected units. They control and inform mainly about the process, e.g. start a motor and inform if it runs correctly, and are the same for DP-V0 and DP-V1.

Command and monitoring telegrams represent the cyclic data transfer.

Diagnosis

The diagnosis telegram provides detailed information if there is any problem, particularly in the process. A trip caused by overload of a motor is an example. Diagnosis data are automatically read by the PROFIBUS:sup:® DP master if it gets a general fault info within a monitoring telegram.

Complete diagnosis telegram

PROFIBUS:sup:® DP			PROFIBUS:sup:® DP with PDP21, PDP22
6 bytes	Standard diagnosis data		6 bytes	Standard diagnosis data
x bytes	User-specific diagnosis data		1 byte + 1 byte	PDP21, PDP22 itself + length of slave diagnosis
			n bytes	Device-specific

Remark: Diagnosis function blocks provide additional 3 bytes diagnosis data that are created by the bus master.

Configuration, Identification and other data

Configuration, identification and other data are necessary to start the operation and communication with the PROFIBUS:sup:® DP slave. These data is created during configuring/selecting the bus line including the slaves/devices and is sent to the FieldBusPlugs directly after power-up.

All slaves compare the expected configuration with their real configuration and confirm if they agree as a supposition to start the data exchange.

Additionally some general data such as baud rate and time-out are transferred.

Parameters

Parameters are necessary to adapt the device to the process.

E.g., for the device UMC22 the parameter “Set current” that has to be set correctly to enable the UMC22 to protect the connected motor perfectly against overload.

Parameters can also include service-oriented data such as “Operation hours”.

The main difference between the PROFIBUS:sup:® DP versions DP-V0 and DP-V1 is:

Parameters DP-V0 and DP-V1

DP-V0 only allows to write the complete parameter set in one block.

The bus master sends the parameter block to the slave during power-up of the slave/device. Some control systems also allow to send the parameter block during normal operation.

DP-V1 offers reading and writing single parameters.

The possibility to read single parameters is an important advantage: If e.g. during commissioning the “Set current” for a motor is modified locally by the electrician, then the control system must be able to read this value to back it up into its data base.

The PDP22 (PROFIBUSParameters DP-V0 and DP-V1:sup:® DP-V1) also allows to suppress the block parameter transfer. This avoids that the parameters are overwritten during power-up of the slave / device.

The appropriate parameter is evaluated in the PDP21 / PDP22 and is not sent to the device and cannot be set via the device.

The appropriate parameter is “Ignore V0 Parameters” or “Use V0 Parameters” respectively and is available in the .GSD file for DP-V1.

In former times a separate master class 2 was needed to read and write single parameters. Currently, most of the control systems offer a class 1 master capable to perform acyclic DP-V1 services to read and write all data types.

Note: In all cases only the bus master can start the data exchange on the PROFIBUS:sup:® DP bus.

PROFIBUS:sup:® DP Master Class 1, PROFIBUS^® DP Master class 2

PROFIBUS:sup:® DP Master, class 1 and class 2

Figure: