CONTROL
PANEL:
Appropriately located at the maintenance platform, the control panel
allows for grab motion monitoring during operation. The panel is connected
to the main feeding cable and some other system components. A PLC/NO
PLC selection switch is used to launch either the main or auxiliary
control system. Though same control accuracy is preserved in both systems,
lowering the grab manually at a wrong cleaning location would damage
the grab, the screen bars and the concrete platform. This represents
a constraint on the use of the auxiliary system and operators are strongly
advised to only resort to it when the main system is out of order.
OPERATION
MODES:
The
automatic operation mode of our monorail-type weed screen cleaning systems
is available through a keyboard. The program opts the number of cleaning
cycles in each cleaning location and the inter-cycle rest time. This
operation mode is only supported by the main control system. Manual
and semi-automatic operation modes of our monorail-type weed screen
cleaning systems are available through the use of a control paddle connected
with a flexible ten-meter-long electric cable. Sockets are fixed to
the track vertical supports centrally-located in the station intake.
The control paddle comprises two selection switches and six control
buttons. A selection switch is used to choose between the two operation
modes. Another selection switch is provided to decide whether to bypass
the next cleaning drop during manual operation or to complete the cleaning
and discharge cycle during semi-automatic operation. The six control
buttons provide control over the motion of the trolley and the grab
during manual operation. Two buttons control the movement of the trolley
towards water intakes and its return to the discharge area. Two buttons
are used to lower and elevate the grab and the last two control opening
and closure of the grab movable jaw. The manual operation mode is supported
by both the main and the auxiliary control systems while the semi-automatic
mode is only supported by the main system.
SECURITY
STOP:
The
winch is self-stopped, pertaining red LED's on the control panel are
turned on and the alarm is activated in case of wire slackness or grab
overloading.
WIRE
SLACKNESS:
A malfunction or improper adjustment of the proximity switch determining
the grab stroke lower end would cause the grab to continue descending
until it settles-down on the water intake bottom. Alternatively, damage
of some weed screen bars may impede the grab downward motion and force
it to stop before completing its stroke. The grab winch wire rope would
slacken in either case and the winch is self-stopped.
GRAB
OVERLOADING:
Overloading
takes place when the tension in the wire rope exceeds the maximum load
carrying capacity. This may take place due to overweight of collected
bodies. Alternatively, some screen bar may be so dislocated that it
hinders the grab upward motion. This can be identified by repetitive
grab stops at some particular location.