Technical data

Communication
9.5 Communication using USS
Function Manual
690 Function Manual, 06/2012, 6SL3097-4AB10-0BP4
9.5.8 USS process data channel (PZD)
Description
In this area of the telegram, process data (PZD) is continuously exchanged between the
master and slave. Depending on the direction of transmission, the process data channel
contains either request data for the USS slave or response data for the USS master. The
request contains control words and setpoints for the slaves and the response contains status
words and actual values for the master.
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67: +6: 67:
S
=6: +,: =6:
S 
S 
3=' 3=' 3=' 3=' 3='
3='
3=' 3=' 3=' 3='
5HVSRQVH
WR866PDVWHU
5HTXHVW
WR866VODYH
Figure 9-56 Process data channel
The number of PZD words in a USS telegram is defined by parameter p2022. The first two
words are:
● Control word 1 (STW1) and main setpoint (HSW)
● Status word 1 (ZSW1) and main setpoint (HIW)
If P2022 is greater than or the same as 4, the additional control word (STW2) is transferred
as the fourth PZD word (default setting).
The sources of all other PZD are defined by parameter p2051 for an RS485 interface.