Siemens SIMOVERT MASTERDRIVES Manual page 765

05.2006
9.5.5 USS interface
Siemens AG 6SE7087-6QX70 (Version AG)
SIMOVERT MASTERDRIVES
The MASTERDRIVES MC compact PLUS units have one USS
interface; the compact and rack-mount units have two. The USS
interface is the preferred interface for connecting the OP1S plain text
servicing unit or a servicing and commissioning PC with the
DriveMonitor service program. In applications where the transmission
rate is not critical, the USS interface can also be used as a low-
performance field bus.
USS has the following features:
♦ The logical message contents are basically identical to the
PROFIBUS-DP message contents. Point-to-point connection (max.
15 m) via RS232 or
♦ Network connection via RS485 with up to 32 stations (max. 1000 m)
♦ Baud rate adjustable from 300 . . . 38400 baud (with additional
modules up to 187.5 Kbaud)
♦ Simple, high-performance protocol with only 4 bytes overhead. You
will find a specification of the USS protocol in the "Communication"
chapter of this Compendium.
♦ Every MASTERDRIVES, SIMOREG and MICROMASTER
converter has at least one USS interface as standard.
♦ User data:
• All setting and diagnostic parameters are accessible; up to 200
bytes of parameter data can be transmitted in one message (one
parameter or all indices of a parameter).
• Up to 16 words of process data (setpoints/actual values,
control/status bits)
♦ Where the network polling time is not critical, the USS can be used
as a low-cost field bus.
♦ A USS interface and drivers are available for almost every SIMATIC
S5/S7 CPU and PC interface (see /3/ and /4/).
♦ The USS is suitable for the connection of Siemens power converters
to third-party PLCs, PCs or customized automation systems.
♦ The network polling time for a USS bus operated at 19.2 Kbaud with
10 drives connected to an S7 with CP340: approx. 650 ms (with 6-
word message frames, 4 words of parameters and 2 words of
process data).
Compendium Motion Control
Technology Option F01
9-117