Basic Documentation
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Siemens VAV compact controller KNX/PL-Link G..B181.1E/KN CE1P3547en
Smart Infrastructure 2021-10-252021-10-25
9.5 Parameter and function description
9.5.1 Vnom (nominal volume flow) [m
3
/h or l/s]
VAV boxes are ordered through an OEM according to this nominal volume flow and
min. / max. volume flow settings. The maximum volume flow for ventilating a room /
zone can’t be higher than the nominal volume flow. Often the maximum volume
flow is lower than Vnom for potential future expansions of volume flows.
9.5.2 Vmin / Vmax (minimum / maximum volume flow) [%]
These values limit the nominal volume flow by multiplying with Vnom. Their effect is
described in chapter 5.
9.5.3 Elevation above sea level [m]
This value enhances the accuracy of the differential pressure sensor to
compensate for the air density decreasing with increasing altitude. It can be set in
500m steps, so for a given building the setting closest to the actual altitude is to be
used.
Example: Altitude of building: 420m a.s.l. → use setting “500m”
9.5.4 Override control
The actuator can be operated in override control for checking / maintenance
purposes or system-wide functions (e.g. night-cooling).
9.5.4.1 Local override:
The actuator enters this state when a service tool is connected at the service
interface (PPS2).
• Open / Close (depends on opening direction)
• Stop
• If the actuator is in backup mode, it will be controllable in local override but
resume the backup mode
- when the service tool is disconnected,
- when the local override timeout is exceeded, or
- when the override control is set to “off”.
• Timeout is 10s after the last read or write access.
9.5.4.2 Remote override:
The actuator enters this state when an override command is sent over the bus. The
override control is available as KNX group object “Override position 1/2” with
associated position parameters. When the group object is set to “enable” over
KNX, the actuator drives to the associated position with override priority. It needs
to be actively reset to “disable” to turn off override control.