Structure Of A Uss Telegram - Siemens SINAMICS G120 CU240B-2 Operating Instructions Manual

6.4.2.2

Structure of a USS telegram

A USS telegram comprises a sequence of characters, which are sent in a defined sequence.
The sequence of characters of a USS telegram is shown in the following diagram.
Figure 6-12
Every character within the telegram comprises 11 bits.
Description
Telegrams with both a variable and fixed length can be used. This can be selected using
parameters p2022 and p2023 to define the length of the PZD and the PKW within the net
data.
STX
LGE
ADR
Net data
(example)
BCC
Start delay
The start delay must be maintained before a new master telegram is started.
STX
The STX block is an ASCII character (0x02) and indicates the beginning of a message.
Inverter with CU240B-2 and CU240E-2 Control Units
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
Header information
STX LGE
Structure of a USS telegram
1 byte
1 byte
1 byte
PKW 8 bytes (4 words: PKE + IND + PWE1 + PWE2)
PZD 4 bytes (2 words: PZD1 + PZD2)
1 byte
n net data
ADR 2
1.
Connection to a fieldbus
6.4 Communication via RS485
Final
information
: : :
n BCC
133