Communication Relationship For Cyclic Data Exchange; Cyclic Transmission Of Process Data; Cyclic Transmission Of The Pkw Channel; Figure 6: Cyclic Communication With Pkw Channel - TR-Electronic MP-Series Benutzerhandbuch

5.1.1 Communication relationship for cyclic data exchange

In this communication relationship unacknowledged I/O data are cyclically transmitted
between Provider (encoTRive) and Consumer (controller). The time period for the
transmission is parameterizable.

5.1.1.1 Cyclic transmission of process data

In the encoTRive this communication relationship serves primarily for the bidirectional
transmission of parameters between the object directory of the drive and the control
(e.g. PLC).
The control sends the output telegram with parameters to the encoTRive at regular
intervals, and the encoTRive transmits its parameters to the control in the response
frame. The telegrams used have the same structure throughout the running time of
the encoTRive.
This type of communication is suitable for parameters that must be constantly
updated, the so-called process data (PZD). Such data are drive parameters, which
are required by the application with a high degree of up-to-dateness. As a general
rule, these always include the control word (STW), the status word (ZSW), and often
the current position value and the target position.
Different applications require different process data. Which parameters are cyclically
transmitted as process data can be defined via the so-called PZD configuration.

5.1.1.2 Cyclic transmission of the PKW channel

The encoTRive also enables transmission of the so-called PKW channel with the
cyclic parameter data in both directions.
The PKW channel also serves to transmit parameters in both directions. With the
PKW mechanism the controller formulates a command, the encoTRive checks and
processes the command and finally formulates the relevant response. The parameter
values can be read or written and the parameter description requested.
The PKW channel is always put in front of the process data in the telegram.
The PKW channel has already been specified in PROFIdrive V2.0 and is
consequently widely used. Older PROFIBUS applications which use a PKW channel
can therefore be ported to PROFINET without any problem.

Figure 6: Cyclic communication with PKW channel

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06/06/2019 TR - EMO - BA - DGB - 0019 - 08
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