Revision 1 – 04.12.2015
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EXAMPLE OF CONNECTION TO SECURITY PRESSURE SWITCH
Alarm related to security pressure switch
A21
is joined to the lacking phase to all the digital inputs.
This is a shut off alarm: below you can find the connection drawing both to contactors 24Vac and/or 230Vac.
Contactors 230Vac
If the operation of the contactors and
solenoid valves comes through 230 Vac, the
digital inputs have to be connected to 12
Vac; next to the contact of the pressure
switch, place and energize an auxiliary
relay and put the contact in serie to
12 Vac (L) (
see drawing on the right
).
When the pressure switch is closed, the
auxiliary relay with contact closed supply
power to the digital inputs; the power
supply of the controller is connected before
the contact of the relay.
When the pressure switch opens, the
auxiliary relay opens power to the digital
inputs; the controller detects all the digital
inputs open and signal the alarm “
SEC.
PRESSURE SWITCH
”.
Contactors 24Vac
If the operation of the contactors and
soenoid valves come through 24 Vac, the
digital inputs have to be connected to 24
Vac (
see drawing on the right
); on this
way when the pressure switch opens due
to high pressure, 24 Vac lacks and
deenergize all the contactors, solenoid
valve and digital: the controller detects
all the digital inputs opened and signal
the alarm “
SEC. PRESSURE SWITCH
”.
I°
12 – 0
II°
Security pressure
switch for high
pressure detection
Power supply to
the controller
Power supply to digital
inputs and uses
24 – 0
I°
12 – 0
II°
Security pressure
switch for high
pressure detection
Auxiliary relay
Power supply to
the controller
Power supply to
the uses
230 – 0
Power supply to digital
inputs
