Automatic door-lock/unlock
CX-9 /2007 Version 1.0
Page 5
Power-off reset
When the contact is switched off, power is removed from the circuit. Assuming the parking brake is
pressed (ON) and as such we are at the end of step 1D.
When the power is removed for the circuit, relay-A will stay activate for little time (~36ms) because of
charge in C3, this will allow Relay-C to get activated before Relay-A drops off. A change in relay-A state
will trigger relay-B to provide a pulse. As such the delay will prevent false door-lock signal (locking the
doors while you are still in)
The charged Capacitor C1 will be discharged and relay-C will activate. Contact-A is set to NO, preventing
a door-lock signal to be sent to the contact-D.
When relay-A is dropping off, it will activate relay-B through contact-C. Relay-B will activate because of
the charged Capacitor C2. Contact-B is closed but no door-lock signal is sent because of contact-A being
in NO state.
After ~1.5 seconds relay-B will de-activate and after ~3 seconds relay-C will.
If at the time of contact switching off the parking brake was NOT pressed (e.g. off), we are at the end of
stage 1C. Relay-A was not activated and C2 was NOT charged thus relay-B will NOT activate.
At the end of power-off all relays and capacitors are back in rest, waiting for a new opportunity to shine
and perform their same tricks at the next occasion.
