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The
heart of the AccuMix™ 750XB is its control system. An Allen-Bradley SLC 5/05
Programmable Logic Controller and Panelview Plus 1250 12.1” color active matrix
Operator Interface is directed by Gears, Inc.’s proprietary AccuMix™ control
software. Designed for harsh industrial environments, this versatile and
reliable system has extensive self-diagnostics and is completely modular, making
diagnosing and repairing problems as easy as plugging in a new module
AccuMix™ software provides fully automated plant control and monitoring of all
plant systems including engine, flow meters, sensors and switches. Displays
indicate all flow rates, set points, feeder speeds, totals and status of all
feeds and processes. All critical mechanical systems are monitored to alleviate
damage and prevent down time. Inventory of fine particulate and admixture are
computed and tracked. An Epson RS232 multi-copy printer is provided and will
print mix design, inventories, rates and totals, either on demand or on a mix
time interval. All electronics are accessible via an Ethernet/IP network and
with optional terminal can be controlled and monitored remotely.
1 of 16 AccuMix™ 750XB control
windows
Start up sequence is automated to start all components
in proper order and all mix ingredients are interlocked and will start
simultaneously. Mix proportions may
be controlled one of three ways. First,
they may be controlled manually by entering the desired feeder speed.
Second, the desired feed rates may be entered and the AccuMix™ software
will maintain them. Third, the desired final product rate and a mix design may be
entered. AccuMix™ software will
then calculate proper proportions and maintain feed rates. Mix design is entered by specifying each dry particulate
additive as a percentage of dry aggregate weight, admixture in gallons per ton
of final product and mix moisture as a percent of all dry materials.
Entering the mix design in this way maintains the crucial proportion of
dry materials and admixture, regardless of moisture changes.
This is very important because the aggregate stockpile moisture will vary
through the day plus evaporation in transport will require varying the final mix
moisture. The operator continually
updates the desired mix moisture and the Hydo-Probes update the stockpile
moisture. AccuMix™ software uses
this information to compute dry aggregate weights and to add the proper amount
of water to achieve desired output.
All material hoppers are equipped with empty bin
indicators tied to mix shut down. Ingredient
feeder control loops are monitored and adjusted every 2 milliseconds for fast
accurate proportioning of feed materials and will shut down the mix immediately
if proportion is not within specifications.
When plant control is by mix design, the combination of these functions
and the consistency of the feeders results in proportioning
accuracies of better than ± 1/10 %
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