【導讀】供水的質(zhì)量和供水系統(tǒng)可靠性的要求不斷提高。把先進的自動化技術、控制技術、通訊。及網(wǎng)絡技術等應用到供水領域，成為對供水系統(tǒng)新的要求。頻器控制，附屬小泵直接接工頻電網(wǎng)，按照先啟先停的原則進行水泵的啟停。可能的保證了幾臺水泵的運行時間一樣，可以很好的提高電機的效率和使用壽命。變頻恒壓供水系統(tǒng)集變頻技術、電氣技術、現(xiàn)代控制技術于一體。生活飲用水品質(zhì)要求的不斷提高，變頻恒壓供水系統(tǒng)已逐漸取代原有的水塔供水系統(tǒng)，的廠家開始重視并推出具有恒壓供水功能的變頻器。而且氣壓罐是密封的，所以大大減少了水質(zhì)因異物進入而被污染的可。能量損失和二次污染問題。同時由于氣壓罐體積大，占地面積一般為幾十平米。由此可見變頻調(diào)速供水方式比氣壓罐供水方式將節(jié)省大量占地面。在運行效果上，氣壓罐方式與調(diào)速式相比也存在著一定差距。穩(wěn)定，突出表現(xiàn)在它的頻繁啟動。由于氣壓罐的調(diào)節(jié)容量僅占其總容積的1/3-l/6

　　

【正文】 張濤：基于 PLC 和變頻器的恒壓供水系統(tǒng)的設計 26 附錄 A：外文參考文獻及其翻譯 Using PLC realization constant pressure water supply Abstract： Take a quarters constant pressure water supply system as an example, introduced applies the PLC realization frequency conversion constant pressure water supply the method. In detail introduced the system hardware architecture, the principle of work and the software realization, and have produced the related control software flow chart and the PLC functional diagram Keyword： PLC。 Frequency conversion velocity modulation。 Constant pressure water supply system。 Presses the potential The daily domestic water quantity along with the season, diurnal, the ing and going to work time different has paratively sweeping change, thus frequently appears the water supply water used not to be balanced, mainly displays in the hydraulic pressure, with juicy supplies water few then the water pulls down, the water used few supplies juicy then height of water. Some pany residential district because the running water pipe work hydraulic pressure is lower, the running water usually cannot arrive the housing a higher floor. Must use the water pump once more Shui Songzhi the roof top digit water tank, again supplies for the user. But, this two water supplies way inevitably causes the pollution, affects inhabitant39。s health. In order to guarantee the plot the water supply is normal, we use PLC, matches by the different function sensor, according to the work management pressure, controls the water pump through the frequency changer the rotational speed, makes in the water pipe the pressure throughout to maintain at the appropriate scope. This kind of frequency conversion constant pressure water supply system direct substitution water tank, top digit water tank and traditional barometric pressure pot water supply installment. Moreover the water pump consumes the electric power and the electrical machinery rotational speed cubic bees the direct ratio relations, therefore the water pump velocity modulation movement energy conservation effect is extremely obvious, the average power consumption more usual water supply way saves 40%. The union uses the programmable controller, may realize the circulation frequency conversion, the electrical machinery soft start, has shortcircuits the protection, has flowed the protection function stably, the work is reliable, greatly lengthened the equipment service life design (1) The principle system will select water pumps parallel operations method, the pressure transmitter advocates the water pipe work hydraulic pressure transformation will be an electrical signal, after the simulation quantity load module, will input PLC, the pressure which the PLC basis will assign supposes the definite value and the actual examination value carries on the PID operation, the output control signal after the simulation quantity output module to the frequency changer, will adjust the water pump electrical machinery the power line voltage and the frequency. When pares the hour with the water volume, pumps under the frequency changer control the stable movement, when with the water volume as big as the water pump full speed movement cannot guarantee when pipe work pressure stable, PLC assigns the low pressure limit signal and at the same time the frequency changer high speed 安徽工程科技學院畢業(yè)設計（論文） 27 signal is examined by PLC, PLC automatically pumps the original work under the frequency conversion condition invests into the labor frequency movement, maintains the pressure the continuity, simultaneously starts the next relay pump after the frequency changer invests the movement, enlarges the pipe work to supply the water volume guarantee pressure to be stable. If pumped the revolution still not to be able to satisfy the pressure the request, then pumped in turn the frequency conversion active status under invests into the labor frequency movement, again invested a relay pump the frequency conversion movement. When with water volume reduction, first displays for the frequency changer has worked in the lowest the signal is effective, by now the pressure upper limit signal like still appeared, PLC first the labor frequency movement will pump stops, reduces supplies the water volume. When the above 2 signals still existed, PLC stopped the 2nd bench work frequency movement again the electrical machinery, pumped until last with the frequency changer constant pressure supplies water. All water pumps electrical machinery from stops and from starts to the start to stops all controlling by the frequency changer, realizes the belt to carry the soft start, avoided starting the big electric current feed pump electrical machinery to bring the impact, relatively lengthened the electrical machinery service life. At the same time, the system water supply uses the frequency conversion to pump the circulation way, by first pass the smooth pass pumps, the work pumps with the relay pump not firmly is decided, like this, both the guarantee water supply system has the relay pump, and the guarantee system pumps has the same running time, effectively prevented because the relay pump does not need to have the rust dead phenomenon for a long time, raised the equipment prehensive use factor, reduced the maintenance cost . (2) the system hardware system has selected siemens39。s S7214PLC, auxiliary loses the output expansion module position, mainly examines the part to have the photo electricity switch, the pressure examination switch, total 12 input signals. The executive ponent has the electrical machinery, the frequency conversion velometer, the acoustooptic alarm apparatus and so on, output spot. PLC mainly pletes the scene the data acquisition, the transformation, the memory, reports to the police, controls the frequency changer to plete fun