Siemens SINAMICS G120 Original Instructions Manual page 300

Setting functions
8.7 Application-specific functions
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 gases 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.
Settings for the essential service mode
Procedure
Proceed as follows in order to be able to use the essential service mode:
1. Interconnect a free digital input as source for the essential service mode.
Example DI3: Set p3880 = 722.3.
Ensure that this digital input is not interconnected with other functions.
2. Using p3881, set the setpoint source for the essential service mode
Option 1:
– P3881 = 0: Last recognized setpoint (factory setting), or
– p3881 = 1: Fixed setpoint 15, or
– p3881 = 2: Analog setpoint, or
– p3881 = 3: Fieldbus
Option 2:
– p3881 = 4: Technology controller
– Using p3884, set the source for the essential service mode setpoint.
3. Using p3882, set the source for the alternative setpoint.
– P3882 = 0: Last recognized setpoint (factory setting)
4. Parameterize the source to select the direction of rotation for the essential service mode.
Option 1: Emergency setpoint using p3881 = 0, 1, 2, 3:
The following applies:
– p3883 = 0 → normal direction of rotation in the essential service mode,
Option 2: Essential service mode via technology controller (p3881 = 4)
If you enter the setpoint for the essential service mode via the technology controller, then
the direction of rotation of the essential service mode setpoint is always valid.
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If you cannot connect a setpoint in p3884, then the inverter takes technology setpoint
1 that has been connected (p2253).
p3882 = 1: Fixed speed setpoint which is defined in p1015
p3882 = 2: Maximum speed (value of p1082)
Using p3883, invert the direction of rotation for the essential service mode. To do this,
interconnect p3883 with a digital input, e.g. with digital input 4 (DI4): Set p3883 = 722.4
– p3883 = 1 → inverted direction of rotation in the essential service mode,
Inverter with CU230P-2 Control Units
Operating Instructions, 11/2013, FW V4.6.6, A5E02430659B AG