8.8 Drive control via USS
Overview
USS is used to transfer cyclic process data and acyclic parameter data between precisely
one master and up to 31 devices. The converter is always the device, and sends data when
requested to do so by the master. Device-to-device communication is not possible.
Function description
Control word 1 (STW1)
Bit Meaning Explanation Signal inter‐
connection
in the con‐
verter
0 0 = OFF1 The motor brakes with the ramp-down time p1121 of
the ramp-function generator. The converter switches
o the motor at standstill.
p0840[0] =
r2090.0
0→1 = ON The converter goes into the "ready" state. If, in addi‐
tion, bit3=1, the converter switches on the motor.
1 0 = OFF2 Switch o the motor immediately, the motor then
coasts down to a standstill.
p0844[0] =
r2090.1
1 = No OFF2 The motor can be switched on (ON command).
2 0 = Quick stop (OFF3) Quick stop: The motor brakes with the OFF3 ramp-
down time p1135 down to standstill.
p0848[0] =
r2090.2
1 = No quick stop (OFF3) The motor can be switched on (ON command).
3 0 = Inhibit operation Immediately switch-o motor (cancel pulses). p0852[0] =
r2090.3
1 = Enable operation Switch-on motor (pulses can be enabled).
4 0 = Disable RFG The converter immediately sets its ramp-function gen‐
erator output to0.
p1140[0] =
r2090.4
1 = Do not disable RFG The ramp-function generator can be enabled.
5 0 = Stop RFG The output of the ramp-function generator stops at the
actual value.
p1141[0] =
r2090.5
1 = Enable RFG The output of the ramp-function generator follows the
setpoint.
6 0 = Inhibit setpoint The converter brakes the motor with the ramp-down
time p1121 of the ramp-function generator.
p1142[0] =
r2090.6
1 = Enable setpoint Motor accelerates with the ramp-up time p1120 to the
setpoint.
7 0→1 = Acknowledge
faults
Acknowledge fault. If the ON command is still active,
the converter switches to the "switching on inhibited"
state.
p2103[0] =
r2090.7
8, 9 Reserved
10 0 = No control via PLC Converter ignores the process data from the eldbus. p0854[0] =
r2090.10
1 = Control via PLC Control via eldbus, converter accepts the process data
from the eldbus.
Advanced commissioning
8.8Drive control via USS
SINAMICS G120C Converters
Operating Instructions, 02/2023, FW V4.7 SP14, A5E34263257B AK 235