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3.2. OPERATION OF THE SYSTEM
The PDS CONTROL units
incorporate, among others, a pressure sensor and a frequency inverter with specifi c pro-
gramming. Associated with fans or ventilation boxes, together with the rest of the elements and maneuvers, they
allow
automatic control of airfl ow and pressure for pressure differential systems.
Their activation can be automatic, through fi re detection panels
or via timed schedule for daily ventilation. However,
fi re detection will always take priority.
They are
also equipped with elements that allow manual control of the system for fi refi ghters
, through key-locked
switches (4), (4a) and (5) on the front panel.
The positions of these switches will determine the mode of operation of the unit, as described below.
3.2.1. AUTO (default position)
Unit remains in stand-by, waiting for an external activation signal (fi re, time programming, remote activation...); the
green indicator (6) is lit.
Make sure that the unit is in this position after any commissioning, maintenance or inspection work, and that the green
indicator (6) is the only one lit.
It is the only position in which the system will respond to an external fi re signal.
If a fi re signal is received, the system will be activated and will operate based on the readings of the pressure sensor. To
avoid false alarms, or rebound signals, the system has an integrated 3-seconds delay period prior to its activation in fi re
mode. After this time, the red indicator (9) will lit indicating the fi re mode, and the white indicator (7 or 7a) will indicate
that the fan has started up.
In AUTO mode, the system would operate as illustrated in the following diagrams, once the fi re signal has been received.
For the PDS CONTROL DUAL, each time the system activates automatically, the fans will activate in alternate turns. This
contributes to the periodic activation of both fans, and to the automatic review of good fan commutation. In the event that
the VSD detected a fault in the activated fan, it would stop it and automatically activate the standby one.
To stop the system (OFF), or to switch to manual activation (ON), the key supplied with the unit must be used.
The key
can only be removed in the AUTO position.