Abstract
Water treatment is necessary steps to the operation of power plant . the plant's raw water
supply contains more impurities and not treated will cause pipeline plug, the ultimate impact of
the production equipment corrosion, a waste of manpower and resources, resulting in economic
losses and lower economic efficiency. Therefore, the water treatment system can work to
improve plant quality and efficiency.
My graduated Design is the application of processing water treatment with S7-200 system,
we need to use the PLC of Simens company’s products to achieve the goals.
In the control system areas, the control of water treatment systems has DCS control
systems, and the PLC, but more use the PLC. A PLC software and hardware feature is powerful,
mature programming, and reliable security firms, there are better and cheaper, the Plc system
mostly built.
Using Plc design, we first need to choose good procedures I/O point, and distribution of
good address. Then begin design control the system.
The need for water treatment using PLC designs all functions. The first point is to clarify
the raw water ponds in the context of the provisions of the heating, the PID of PLC function used
here needs to the entrance of clarify pool temperature regulation to ensure clarification pond into
export temperature less than two degrees. Also has the clear water tank fluid position piggy-back
control settling pond entrance adjustment gate opening, needs to use PLC ‘s APR function block,
carries on the partition establishment, then carries on the control again. After exportation
turbidity exceeding the allowed figure automatic increase medicament, then needs to establish
the upper limit, when surpasses the hypothesis the upper limit, automatic increase medicament.
The settling pond regular pollution discharge used PLC fixed time the function.
After the process design, finally realizes the chemistry water treatment automatic control,
its result may show through on position machine. Simultaneously also may complete the revision
and the manual operation function.
During the system working, it will reduce operator's work load, enhanced the working
efficiency. Simultaneously also can monitor promptly, guarantees the production safety.
Key Words PLC, Water Treatment, Programming control
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