MAC/MTT-OPS-1
26 FEB 2019
SECTION 2
System Description
2-14
The joystick box functions operate as follows:
Basic System Theory Of Operation
Spray system power is provided by chassis 24 volt
DC power. Power is routed to the cab control
boxes by turning on the switched power via the
ignition key switch.
When the chassis ignition switch is turned on, the
master switch box will undergo a functional self-
test. During this process, ALL LEDs will first turn
ON, then OFF. While this is occurring, the water
level indicator lights will initially register a FULL
tank, and will then decrease down to EMPTY. The
EMPTY light will blink, and then the water level
indicator will count up to register the current
water level of the tank.
Cab control power is then activated by turning the
cab control POWER switch ON. The spray system
will function normally when cab control power is
applied (cab control POWER switch ON) and
sufficient water is present (water level EMPTY light
not flashing). Activation of a specific function is
accomplished by depressing the appropriate
function switch on the master switch box or
joystick box.
Depressing a switch sends a signal to the logic
control panel in the solenoid box to activate the
associated function. The appropriate controller in
the solenoid box receives the signal and provides
output voltage to the given coil.
Once voltage is sensed at the coil, the controller
sends a signal back to the cab control box to
illuminate the LED on the selected function switch.
LT VSS
Opens or closes left vertical side
spray head.
DRAIN Opens or closes tank drain BFV.
DUMP
BAR
Opens or closes dump bar BFV.
RT VSS
Opens or closes right vertical side
spray head.
LT REAR
Opens or closes left rear spray
head.
LT CTR
Opens or closes left center rear
spray head.
RT CTR
Opens or closes right center rear
spray head.
RT REAR
Opens or closes right rear spray
head.
Control Function
(N/A)
Joystick
(LEFT-
RIGHT-UP-
DOWN)
Sends command signals to the
hydraulic control valve assembly
to move the water cannon.
FOAM
Open or closes the foam
concentrate tank in-line control
valve.
FOAM
LOCK
Unlocks FOAM switch for
activation of foam
suppression.
NOZZLE
Adjusts water cannon nozzle
from FOG to STREAM.
BFV
Opens or closes the water
cannon butterfly valve.
Symbol Name Function
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