Osona Water Purifying Network

Automation of the entire water purification network in the province of Osona, north of Catalonia, was carried out by Adasa SA using Omron products. The plant has 35 connected pumping stations, with the control center located in the central offices of Vic. The area concerned for the project has an approximate extension of 1,200 km2.

The purpose of this project was to develop an automation and control system that could collect information from the station networks for both purification and pumping, and forward it to the main control center in Vic, to have real time control and to optimally use the plants.

To carry out this project, Adasa had to face many problems:

• Different kinds of facilities, with highly extensive stations where the work was based on the existence of many people working and other small facilities located in dispersed and difficult-to-access villages, working independently.
• Different types of control. Some stations worked locally with their own control system, since more than 70% of other stations already use Omron control equipment.
• Problems with orographical position. Osona is very mountainous and has many stations that are difficult to access; therefore we had to carefully and extensively plan out the communications system.

The priority was to ensure that the system worked, since the territory has many pig farms and the risk of contamination is very high. In the purifying stations controlled by the PLC CQM1 a CPU 51 was installed that can manage the SCB41 communications board with the RS232C and RS422/485 interface. In the stations controlled by PLC C200H, a COM06 communications board was installed using the Macro protocol to support the driver developed for communications via radio.

In these purifying stations, which had to be automated from zero, a CJ1 programmable controller was installed along with SCU41.

For the pumping stations, control is carried out in three ways:

• Stations controlled via the PLC, which manages the corresponding purifying station, and sends data to the Vic control center via its communications board;
• Stations controlled via a local PLC, which directly communicates data to the Vic control center;
• Stations that easily run the control logic with electromechanical functions and with a remote station set up, which has modules to connect the control system to the on-site equipment using a communications system via radio.

Each new PLC was equipped with a programmable NT631 or NT31C terminal touch screen, which allows operators to access different parameters, monitor alarms, view graphs of the last 24 hours, etc.

Although the project was large in scope, the application is very intuitive in the practical setting. It had been designed to be easily used by the operators working at the purifying station. Vic has a centralized computer that is connected to all stations via a radio communications interface. Via Ethernet and Internet, it is possible to display the progress of all analog system values, such the functional status of all equipment.