System Introduction
The whole process of tap water production involves: 1) diverting water from water resources; 2) production in waterworks; 3) booster station in the midway of pipeline network; and 4) monitoring pressure at certain points. Based on this, a complete Supervisory Control and Data Acquisition (SCADA) system for urban tap water production is formed. To realize progressive information transmission and hierarchical system control, multiple monitoring outstations, and water intake and supply monitoring stations are built in the waterworks.
The geographical dispersion of water resources require that data acquisition and control functions shall be highly stable and secure. The current control system combines Ethernet with industrial field bus, and uses Industrial PC and associated I/O modules for stable and reliable operation and the automatic control of waterworks.

System Principle
System network architecture adopts the combination of RS-485 industrial bus and network (TCP/IP). The system acquires field signals (such as water flow, water temperature, impurity content, water pressure, etc.) from corresponding sensors. EVOC RS-485 bus data acquisition and control module is used to acquire data and deliver the data to Industrial PC. Corresponding configuration software performs data processing and sends the data to the operator’s control room. Data can be browsed and monitored in the central control room. Meanwhile, if corresponding control is required, relevant commands will be sent to each pump room through the network, and the control function of each module is used, so as to control each pump room. In this way, each pump room can work stably and reliably in an unattended way.

System Structure
The system consists of:
1) Water source pump workstation;
2) Workstation for adding alum, chlorine and horizontal flow sedimentation tank;
3) Filter workstation;
4) Water delivery pump workstation;
5) Operator workstation;
6) Control room.

Block Diagram


System Configuration
Operator controls:
Each control station:

System Evaluation
The main control system of the project and the main control unit of the monitoring system adopt EVOC solutions which have proved to be stable and reliable in a long working period and have fully guaranteed the water supply for industrial and agricultural purposes. EVOC solutions play significant roles in the project.
The system features easy and open expandability, strong communication capacity and favorable HMI platform. To monitor variables and other parameters, each subcontrol station of the system can be equipped with CRT/LCD display. Also, the system can operate the controlled objects on the spot. The self-control system uses a standard configuration software that can satisfy both the current needs of the project and future expansion of the self-control system for the waterworks.