Acyclic Communication According To Dp/V1 - WAGO I/O SYSTEM 750 750-833 Manual

3.10 Acyclic Communication According to DP/V1

In addition to cyclic data communication (PROFIBUS-DP standard in
compliance with IEC 61158), PROFIBUS-DP also offers acyclic
communication services as an option. These acyclic services can be performed
parallel to cyclic data transfer. In process engineering applications, the
optional services allow industrial devices to be operated using PROFIBUS-
DP. Standard field devices and devices that require these optional extensions
can be operated on the same bus. The data blocks are addressed via the slot
number and the data block number (index) of the module. The meaning of the
slots and indices can be set according to the device specifications. This way,
the user can either access the data or the parameter sets within a field device.
To distinguish between a standard DP and an acyclic DPV1 device, some
keywords have been added to the GSD file.
Via GSD entries, a master can identify the services supported by the field
device. In the parameter telegram, the K1 master activates the acyclic
communication services of the device. In Data_Exchange mode, the K1 master
can use the acyclic services of the slave that has been parameterized and
configured by the master. Acyclic communication is no longer possible once
cyclic data exchange has been interrupted.
The extended services are divided into master class 1/ slave functions
(MSAC1) and master class 2/ slave functions (MSAC2).
Both initiating and aborting the communication channel is required so that the
MSAC2 connection can be monitored. Monitoring a MSAC1 connection is
done via the MSCY0 connection, which is always required.
WAGO-I/O-SYSTEM 750
Bus System
Programmable Field Bus Controller 750-833
Acyclic Communication According to DP/V1
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