Siemens 6RA7086-6KS22 Operating Instructions Manual page 380

Function descriptions
USS:
A maximum of 32 nodes can be connected in the bus configuration (i.e. 1 master and max. 31 slaves).
The bus connector must be activated on the two bus nodes which form each end of the bus circuit.
Peer-to-peer:
Up to 31 other drives can be connected in parallel to the transmit cable of one drive. With a "parallel
connection", the bus connector must be activated on the last connected drive.
9.13.1 Serial interfaces with USS
Specification for the USS
The SIEMENS USS
can be used to provide a point-to-point or bus-type link to a master station. Any mixture of converter
types can be connected up to the same bus line. The USS protocol makes it possible to access all
relevant process data, diagnostic information and parameters of the SIMOREG converter.
The USS protocol is a pure master-slave protocol. In this case, a converter device can only ever
function as slave. Converter devices will transmit a telegram to the master only if they have received
one from it first. In other words, converters linked via the USS protocol cannot exchange data directly
with one another (they can do this only via a peer-to-peer link).
Useful data which can be transferred via the USS protocol
Sheets G170 to G172 in Section 8 show how useful data can be interconnected and list the
parameters relevant for configuring USS interfaces.
If parameters need to be read and/or written via the USS interface, then "Parameter data length"
(P782, P792, P802) must be set to 3, 4 or 127 (select setting 4 only if double word parameters need to
be transferred). If parameters do not need to be transferred, the "Parameter data length" must be set
to 0.
The number of process data words to be transferred is basically identical for the transmit and receive
directions and can be set in "Process data length" (P781, P791, P801). Numeric representation "100%
equals 4000h = 16384d" applies to all connectors.
Transfer of double-word connectors:
In the receive direction, the values of any two adjacent connectors (K) are combined to form a double-
word connector (KK) (e.g. K2002 and K2003 to KK2032). These double-word connectors can be
connected in the usual way to other function blocks. For details of how to connect with double-word
connectors, see Section 9.1, subsection "The following rules apply to the selection of double-word
connectors".
In the transmission direction, a double-word connector is applied by entering the same double-word
connector at two contiguous indices of the selection parameter.
Examples:
9-24
® protocol
®
protocol: Order No. E20125-D0001-S302-A1
®
protocol is implemented in all digital converter devices supplied by SIEMENS. It
K0032
KK9498
KK9498
K0401
K0032
KK9498
KK9499
K0401
P784
.01
32
K Word
.02
9498
L-Word
K
.03
9498
K H-Word
.04
401
K
Word
P784
.01
32
K
Word
.02
9498
K H-Word
2 different
.03
double-word connectors
9499
K
H-Word
.04
401
K Word
SIMOREG DC Master
05.05
SIEMENS AG 6RX1700-0AD76
Operating Instructions