管网压力检测点；

250KW变频器，泵房供水泵控制；

110KW软启动器，泵房供水泵控制；

100M工业以太网，厂内快速可靠通讯；

ProfiBus-DP工业现场总线，厂内控制设备连网；三、解决方案优势

先进性：采用当前先进的网络技术和控制设备；

经济性：S7-400PLC/S7-300PLC/ET200智能I/O站、变频器/软启动器 SIMOCODE、ProfiBus-DP/100M工业以太网的灵活设备选型及应用；

标准化、模块化：

* SIEMENS PLC控制系统；

* SIEMENS SINUAT无线通讯系统

编程组态简便、扩展性强、可靠性高

强大的保护功能：SIMOCODE、变频器、软启动器、输入/输出电抗器、电器联锁、程序联锁等；

完整的数据采集： 生产过程数据、设备状态信息等；

工业现场总线技术：提高整个系统的可靠性，减少布线施工费用，降低使用维护成本；

100M工业以太网：提高网络通讯的快速性和可靠性大庆油田部分污水站反冲洗装置处于手动状态，存在不能定时反冲洗、反冲流量控制不、滤料还没冲起就搅拌等一系列的问题，对生产造成不利的影响。本文将PLC技术应用于反冲洗控制，通过硬件系统改进，实现变频控制自动反冲洗，提高系统反冲洗的质量，减轻工人劳动强度。主题词：自控 污水站 反冲洗 1 引言  含油污水处理是关系到水质是否合格的关键步骤，而滤罐的反冲洗时间和效果则直接影响污水的过滤质量，所以定时反冲洗，按要求控制反冲洗的流量曲线是控制水质质量的核心。大庆油田部分污水站（聚杏Ⅱ-Ⅰ站）反冲洗装置处于手动状态，变频器与电动阀不能配合，变频器无法投用，反冲洗流量无法控制，出现冲走滤料等问题，影响反冲洗效果。整个反冲洗过程水泵始终处于满负荷运转，造成大量电能损失，而且每个罐都需单独操作，操作工人劳动强度很大。这些都对生产造成不利的影响。因此对现有手动反冲洗装置的自动化改造，不仅可减轻操作工人的劳动强度，更重要的是能提高系统反冲洗的质量，使设备达到佳的运行效果。2 工艺过程  污水深度处理正常过滤的过程是：由一段、二段脱出水经缓冲罐、升压泵进入一次滤罐、二次滤罐后到注入站注入地下。滤罐内滤料经过一段时间后，会沉积一些污油，需要定期进行反冲洗，在实际生产中，手动控制反冲洗操作步骤如下：

1） 关闭待反冲洗罐过滤进、出口阀门，开启反冲洗进、出口阀门；

2） 开启反冲洗水泵，按阶梯形提高水泵电机频率直到达到50Hz；

3） 开启反冲洗滤罐搅拌器，搅拌10分钟后关闭搅拌器。

4） 上一台反冲洗15分钟后，关闭下一台待反冲洗罐过滤进、出口阀门，开启反冲洗进、出口阀门；

5） 重复以上步骤，直至全部过滤罐反冲洗完毕。3 系统组成  反冲洗自动控制系统的输入信号主要有上位机操作台和触摸屏的控制输入及阀位开关反馈信号。共有开关量（DI）120个输入点。PLC系统的控制负载主要包括调节阀控制、搅拌器启/停、变频器控制负载。共有开关量（DO）270个输出点，模拟量（AO）2个输出点。The system has the advantages of energy saving, reliable operation and high degree of automation, which improves the quality of water supply. 1. With the rapid development of variable frequency speed regulation technology and programmable controller, as well as its wide application, powerful function and convenient use, it has become one of the main devices of modern industrial automation and is widely used in industrial production, applications in other areas, such as civil and Home automation, have also developed rapidly. Due to the flexible and convenient application of frequency conversion and programmable logic controller, it is also widely used in constant pressure water supply system. Using PLC as the central control unit, the working pressure of the water supply system can be quickly adjusted according to the system state by the combination of frequency converter and Pid, thus achieving the goal of constant pressure water supply and improving the working stability of the system, the good control effect and obvious energy-saving effect are obtained. 2. System Structure Frequency conversion constant pressure water supply system principle as figure 1, it mainly has PLC, frequency converter, pressure transmitter, liquid level sensor, power and control circuit and pump group composition. The user understands and controls the operation of the system by means of the indicator lights and buttons on the Control Panel and the transfer switch. Through the pressure transmitter installed on the outlet pipe network, the outlet pressure signal is changed into 4 ~ 20mA standard signal and sent to the PID regulator built in the frequency converter. By comparing the PID operation with the given pressure parameter, the 4 ~ 20mA parameter is obtained, 4 ~ 20mA signal is sent to frequency converter. The control system uses the frequency converter to control the pump speed in order to adjust the water supply. According to the different water consumption, the frequency of the frequency converter to adjust the pump speed is different, setting an upper limit frequency and a lower limit frequency detection in the frequency converter setting, when the water consumption is large, the frequency converter quickly rises to the upper limit frequency, at this time, the frequency converter outputs a switching signal to the PLC; When the frequency converter output reaches the lower limit frequency, the frequency converter also outputs a switching signal to the PLC; the two signals will not be produced simultaneously. When any signal is generated, the signal is fed back to the PLC, and the PLC can switch the AC contactor group by setting an internal program to drive the i/o switch output, so as to coordinate the number of pump motors put into operation, and the completion of the motor start-stop, frequency and power-frequency switching. By adjusting the number of motors put into operation and controlling the frequency conversion speed of one motor in the set, the working pressure of the system pipe network is always stable, and then the aim of constant pressure water supply is achieved. Working principle the system has two modes of operation: Manual and automatic. Manual Mode, press the button to start and stop the pump, according to the need to control the start and stop of 1 # ~ 3 # pump, this mode is mainly used for equipment