Siemens SINAMICS G120 Operating Instructions Manual page 285

The inverter carries out the maximum number of restart attempts set in p1211 corresponding
to the settings in p1212 and p1213. If these attempts are not successful, then the inverter
goes into a fault condition with F07320.
Speed setpoint in the essential service mode
p3881 defines the speed setpoint in the essential service mode. If you have defined an
analog input as setpoint source using p3881, then for wire breakage, the inverter can switch
over to setpoint p3882.
Bypass and essential service mode
● If, when activating the essential service mode, bypass operation is active, inverter
operation is selected internally in order to ensure that the setpoint is entered via the
source intended for the essential service mode.
● If faults are still present after the number of start attempts parameterized in p1211, then
the inverter goes into a fault condition with F07320. In this case, there is an option of
switching over to bypass operation and then directly connecting the motor to the line
supply.
Application example
To improve the air circulation in the stairwells, the ventilation control creates a slight
underpressure in the building. With this control, a fire would mean that smoke would enter
into the stairwell. This would then mean that the stairway would be blocked as escape or
evacuation route.
Using the essential service mode function, the ventilation switches over to the control of an
overpressure. This prevents the propagation of smoke in the stairwell, thereby keeping the
stairs free as an evacuation route.
Converter with CU230P-2 Control Units
Operating Instructions, 04/2015, FW V4.7 SP3, A5E34257946B AB
Advanced commissioning
6.7 Application-specific functions
285