User Data Range Of The Uss Telegram - Siemens SINAMICS G120 Operating Instructions Manual

Configuring the fieldbus
7.7 Communication via RS485
Telegram part
Start delay /
response delay
STX
LGE
ADR
Net data
BCC
7.7.2.3

User data range of the USS telegram

The user data area consists of the following elements:
● Parameter channel (PIV) for writing and reading parameter values
● Process data (PZD) for controlling the drive.
Figure 7-11
160
Description
There is always a start and/or response delay between two telegrams (see
alsoTime-out and other errors (Page 167))
An ASCII character (02 hex) indicates the beginning of the message.
The telegram length "LGE" is calculated as follows:
LGE = user data (n bytes) + ADR (1 byte) + BCC (1 byte)
Bit 7 = 0: Normal data exchange.
•
Bit 7 =1, to transfer telegrams that require a net data structure different from
the device profile.
Bit 6 = 0: Normal data exchange.
•
Bit 6 = 1: Testing the bus connection: The converter returns the telegram
unchanged to the master.
Bit 5 = 0: Normal data exchange.
•
(Bit 5 = 1: Not supported in the converter.)
Bits 0 ... 4: Address of the converter.
•
See section User data range of the USS telegram (Page 160).
Checksum (exclusive or) across all telegram bytes – with the exception of BCC.
USS telegram - user data structure
Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB