SOI/DT 2010-03 dmm
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11.2.2 Instantaneous
door
interlock
•
With this safety device, the door can be opened immediately after the end of the cycle.
9
Door safety interlock
20 Anti-disturbance filter
20 PCB
ON/OFF = Main switch (incorporated in the
programme selector)
11.2.2.1 Operating principle
•
When the ON/OFF switch closes and the appliance is switched on (at the programme selector knob), power
is supplied to the bi-metal PTC (contact 4-2), but the door remains unlocked.
•
When the programme starts (Start/Pause button), the PCB sends a 20 msec pulse to contact 4-3 of the
solenoid (at least 6 seconds must have passed since the appliance was switched on); this locks the door
and simultaneously closes the main switch (contacts 4-5), thus supplying power to all the appliance
components.
•
When the programme ends, the PCB sends two additional 20 msec pulses (200 msec apart):
-
the first pulse does not unlock the door
-
the second pulse (which is sent only if the appliance is operating properly) unlocks the door lock device
and simultaneously opens the contacts on the main switch.
11.2.2.2 Door open conditions
Before pulses are sent to open the door, the PCB checks for the following
conditions:
-
the drum must be stationary (no signal from the tachometric generator)
-
the water level must not be higher than the lower edge of the door
-
the temperature of the water must not be higher than 40º C.
11.2.2.3 Automatic release device
If a power failure occurs, if the appliance is switched off, or if the solenoid valve malfunctions, the bi-metal PTC
will cool down and unlock the door in approximately 1 - 4 minutes.
