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The
plant operating controls are in a console, which is installed in a
portable control house. The house is mounted on a trailer and can be
transported by a pick-up truck with a trailer hitch. The house has
heating, air-conditioning and interior lights.
Plant controls are in a steel console. The controls include three
Honeywell temperature controllers, a Honeywell burner management
controller, a Siemens programmable process controller and three Astec
MBUs.
The Siemens controller
controls automatic blending of the mix and incorporates a PLC
(programmable logic controller) and back- lit liquid crystal display.
Drag hopper controls. Allow operator to control trucker signal and hopper discharge. Also gives alarm when hopper reaches high level.
Asphalt pump controls. Enable operator to manually control speed of AC pump and to override automatic mix control.
Plant emergency shutdown control. Enables operator to shut down entire plant.
Plant startup alarm. Enables operator to control startup alarm.
Damper control. Enables operator to control exhaust fan damper.
Motor controls.
Enable operator to turn on/off power to motors that operate the air
compressor, exhaust fan, drum drives, drum mixer burner blower, drag
conveyor, slinger feeder, water pump, dust screw, and fuel pump. Also
enable operator to control mid-stream start/stop.
Burner controls.
Enable operator to choose either manual or automatic process control,
to preset mix process temperature, to preset the mix temperature limit,
to preset the stack temperature limit, to see burner status, to reset
flame safeguard controller, to turn on burner pilot, to turn on burner
main flame, to see status of limits, to see status of flame failure, to
silence burner alarm.
Connectors.
Connectors of plant cables mate with connectors in the bottom of the
console. They are accessible from the underside of the control house.
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