GE Industrial Solutions AF-600 FP Profibus DP - Manual (Page 41)

5.1.2 Read / Write in Double Word Format, DP V1
Using the special Request IDs 0X51 (read) and 0X52 (write), it is possible to read and write to all parameters containing numeric values in a general format of
Double Word. The value element must be right aligned and unused MSBs filled with zeros.
Example: Read of a parameter of type U8 will be transmitted as 00 00 00 xx, where xx is the value to be transmitted. The data type signalled by the message will
be 43h (dword).
Please refer to the table Request/ Response Attributes later in this chapter.
Access the parameters as follows:
5.1.3 PROFIBUS DP V1
Using the acyclic DP V1 transmission it is possible to read and write parameter values, as well as to read a number of descriptive attributes for each parameter.
Access to parameters via DP V1 is described in the DP V1 Parameter Access section.
5.1.4 PROFIBUS DP V0 / PCV Channel
Parameter access via the PCV channel is performed using PROFIBUS DP V0 cyclic data exchange, where the PCV channel is part of the PPOs described in the PPO
Types section. Using the PCV channel, it is possible to read and write parameter values, as well as read a number of descriptive attributes for each parameter.
The functionality of the PCV channel is described in the PCV Parameter Access section.
NB!
Object and data types supported by AF-650 GP & AF-600 FP drives and common to both DP V1 and PCV parameter access are listed in the Parameters chapter.
5.2 DP V1 Parameter Access
This section is useful for the developer with some experience in:
PLC programs with PROFIBUS master class 1 functionality
PC applications with PROFIBUS master class 2 functionality
For more detailed instructions in use of the DP V1 function in AF-650 GP & AF-600 FP drives, please refer to the Operating Instructions Information about the
features supported by the PROFIBUS DP V1 functions.
5.2.1 PROFIBUS DP V1 Introduction
The PROFIBUS DP extension DPV1 offers acyclical communication in addition to the cyclical data communication of DP V0. This feature is possible using a DP
master class 1 (e.g. PLC), as well as a DP master class 2 (e.g. PC Tool).
Cyclical communication means that data transfer takes place continuously with a certain refresh rate. This is the known DP V0 function normally used for quick
update of I/O Process Data.
Acyclical communication takes the form of a once-off data transfer event, mainly used for Read / Write from and to parameters from process controllers, PC-
based tools or monitoring systems.
AF-650 GP/AF-600 FP Profibus DP Operating Instructions
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