PLC Control System
PLC Control System
Date:2015/12/25 17:17:49 Visits:Times

SABO PLC Control System to the professional design, advanced software programming, exquisite processing cabinet, well-known component selection, products and reasonable layout, beautiful integrated wiring, and thoughtful site debugging, often receive a electric power, metallurgy, petrochemical, building materials, transportation, municipal and other customers of praise. The following is the construction of a city in the north of the city of PLC water reuse control system:

1 Project Background:

China's water pollution situation is grim, water shortage is very serious, and the Reclaimed water reuse is one of the effective ways to alleviate the water crisis. " Reclaimed Water" from Japan. It is a in the city and the lives of the residents of miscellaneous drainage after proper treatment, to a certain quality standard after reused for flushing toilets, washing cars, green or cooling water supplement use of non potable water. Reclaimed water is internationally recognized as the second water source of the city, the water reuse can not only solve the impact of sewage on the urban environment, but also can improve the total amount of water available, the city is an important measure of water saving.


2 Process Introduction

The project consists of a city in Northern Jiangsu Environmental Protection Bureau invested 15 million 600 thousand yuan to build a daily processing 3000 tons of sewage water reuse project. The project adopts "traditional activated sludge biological treatment process and lixiviation type hollow fiber membrane physical filtration process" combination of MBR, water treatment process, the technology is recognized by the international community as one of the most important technologies in the popularization and development prospect, but also in developed countries focus on the development and mature of a practical technology. In 2009 the water reuse project put into operation, resulting in significant benefits:

  1. the annual reduction in water consumption of 900 thousand tons; 2

  2. the annual reduction of 900 thousand tons of sewage discharge;3

  3. annual reduction of COD emissions of 400 tons.

3 Overview of PLC Systems

PLC control equipment is the link between industrial field and testing center, on the one hand it acquisition field instrument, transducer, and the running state of the equipment such as signal, on the other hand it communicate with the testing center, executive orders. Monitoring equipment is generally unattended, in this control system using the SIEMENS S7-414H as the central controller, dual power redundancy, CPU PLC using dual hot standby. IPO template using ET200M expansion connection. Using the active bus module and the guide rail makes the system can support the hot swap of the IPO module. Communication protocol using Profibus protocol, data transmission rate of up to 12MPs, fully guarantee the high reliability and high speed data communication, PLC and PC computer with the addition of IPO card in addition to the real redundancy.

4 Main Functions

1)Shows the amount of each analog and digital surveillance systems: on the raw water, concentrated water, product water flow, pressure, temperature, conductivity, turbidity, pH value and other detection; pump motor start stop, running state, the current and voltage monitoring; automatic valve switch state, chain; system starting, running and stopping process of automatic operation, the normal state don't need artificial interference, avoid misoperation.

2) abnormal data display and automatic pop-up alarm screen to confirm the alarm. For all systems of abnormal data, have alarm blinking of pictures and data; pump motor running state is not normal, the fault state of the process equipment can pop-up warning screen and fault alarm acknowledge picture.

3) to set up the trend picture and get the trend information. All flow, pressure, temperature, turbidity and pH value of the analog display can establish vertical and trend frame, and long-term retention exists within the host computer, can transfer at any time to check, convenient production management and operation and maintenance.

4) adjust the process setting and bias, etc.. All process values, such as raw water inlet water, fresh water outlet temperature, high pressure water inlet pressure, can be realized by manual and automatic on-line adjustment. The chemical formula can be stored in the computer, and according to the formula according to the proportion of automatic dosing.

5 Main Features

1) controller S7-414H redundancy system can achieve dual controller redundancy automatic switching function, when the main control of the CPU failure, another CPU automatically take over the main control CPU, the switching time is in milliseconds. Fully guarantee the safe operation of the system.

2) communication redundancy using DP ET200MIPO protocol PROFIBUS station redundant communication interface and cable, and the dual controller (CPU) redundant communication, for the signal acquisition and transmission provides a guarantee.

3) power redundancy, 10A DC power redundancy configuration, for CPU and template power supply, to ensure the reliability of power supply.

4) system in the debugging process in due process required changes in the larger program change more frequently, but Siemens STEP7 programming software provides a perfect with the IEC 1131 standard programming tools, including ladder diagram (LAD2ER) in the and statement list (STL), continuous function chart (CFC), sequential function chart (SFC), structured language (SCL) and a variety of programming tools can mixed use, cross references, very convenient, also system standard function block library and improve the programming efficiency, shorten the project cycle.

5) screen monitoring software WinCC6.0 (Windows Control Center) is the shape opening map for the operating system of windows 2000PXP of man-machine operation interface based on the, with easy configuration, simple operation, with complete industrial graphics library, such as valve, a water storage tank, a traditional analog display instruments, piping, etc., to facilitate the design of monitoring system of process picture.

6 Application Experience

1) water treatment automatic control system with PC + PLC control, PLC using hardware redundancy, both to meet the process control requirements, and improve the running safety and reliability of system, worthy of use and desalination system to promote the application of reuse in the large scale water.

2) is adopted in PLC hardware redundancy, with the individual PLC programming without any distinction, in the project design and debugging does not need to do too much to consider, so you can put more energy in the process of understanding, greatly saves time and energy.

3) PLC and configuration software are used in the same product, can make full use of its internal protocol, data resource sharing, high compatibility, complete function, the configuration interface is friendly.