User Data Range Of The Uss Message Frame; Data Structure Of The Uss Parameter Channel - Siemens SINAMICS G120 Operating Instructions Manual

Functions
5.11 Operation in fieldbus systems
5.11.2.1

User data range of the USS message frame

Structure of the user data
The user data range of the USS protocol is used to transfer application data. The process
data is exchanged cyclically between the inverter and controller via the process data channel
(PZD), while the parameter channel is used for transferring parameter values acyclically.
The following diagram shows the structure and sequence of parameter channel and process
data (PZD).
Figure 5-19
The length of the parameter channel is defined via parameter P2013, while the length of the
process data is defined via parameter P2012. If only parameter channel or only process data
are required, the parameters of the channel not required can be set to zero ("only PKW " or
"only PZD").
If both channels are required, they must be transferred together.
5.11.2.2

Data structure of the USS parameter channel

Description
The parameter channel is used to monitor and/or change parameters in the inverter. Every
time data is transferred, the parameter ID and associated parameter value are sent. The
parameter channel can be set to a fixed length (3 or 4 data words) or variable length.
● The first data word always contains the parameter ID (PKE)
● The second data word contains the parameter index (IND)
● The third and fourth data word contain parameter values, text, and descriptions (PWE)
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USS user data structure
CU240S and CU240E Control Units, FW 3.2
Operating Instructions, 03/2009, A5E02440075B AA