SEQUENCER WITH
DIFFERENTIAL PRESSURE
SWITCH
Technical notice
FI 72.0567.0221E
Page 41 / 45
Re-inflation tank faults :
Depending on the configuration, the compressed air tank associated with the cells constituting the filter are each
equipped with a pressure switch and an isolation solenoid valve on the compressed air inlet.
During the declogging phases, the pressures of the tanks are monitored.
The pulse on an declogging SV causes a pressure drop in the tank and initiates a time T9.
If, at the end of time T9, the tank is not re-inflated, the SFX+V2 generates a re-inflation fault and isolates the
concerned tank.
The tank is considered "re-inflated" if the pressure is greater than the operating pressure threshold (the check is
carried out from T1+0.5 second and until the end of T9).
Note: if the activation of the SV on the same tank is too close (<T9), we wait for re-inflation to activate it or the end
of T9 to generate the fault.
This type of fault is auto-reset if the tank pressure becomes correct again (a priori, this never happens because the
compressed air supply to the tank is cut off).
Note: T9 can be set to 0 or the operating pressure threshold to 0. In this case, the re-inflation check is not
performed.
The re-inflation tank fault is indicated by:
- « Header reinflation fault in the header n°
xx.
Cell n°yy SV n°
zz
»
xx
being the number of the tank number
yy
being the number of the cell and
zz
the number of the SV of the cell that caused the fault (theoretical).
SV non-opening faults :
Depending on the configuration, the compressed air tank associated with the cells constituting the filter are each
equipped with a pressure switch. This pressure switch is able to determine if a consumption of compressed air
appears on the tank when a pulse on one of its declogging SV is given.
At each pulse on a declogging SV must correspond a pressure drop in the concerned tank. If this is not the case and
after 3 consecutive checks on the same declogging SV, the SFX+V2 generates a SV non-opening fault. The check
is carried out during T1 and until the end of T2.
The pressure consumption is observed when the pressure drops below the “operating pressure” threshold or if the
pressure has fallen more than the value of the “pressure drop” set.
This type of fault is auto-reset if the pressure drop is observed during SV actioning.
Note: T9 can be set to 0 or the "operating pressure" threshold to 0 or the "pressure drop" threshold to 0.
In this case, the pressure drop check is not performed.
The SV non-opening fault is indicated by:
- « A/C no consumption faul : cell n°
xx
SV n°
yy
»
xx
being the number of the cell and
yy
the number of the SV of the cell
