City of Rock Hill updates control and monitoring system for city
wastewater treatment
The City of Rock Hill in South Carolina wanted to make improvements to the control and monitoring system used for the city's wastewater treatment facility. The old system was difficult to work with and expensive to maintain, and after careful research, the city decided it would make more economical sense to replace the old system with something new that had a greater I/O capacity, was easy to update, and cheaper to maintain.
An existing FoxBoro I/A system and a fixed UNIX operating system were extremely difficult and expensive to make changes to and bring up to date. For example, each time anyone wanted to add a button to the screen, they had to make a service call and wait for assistance. In addition to the inconvenience, the cost would be anywhere between $1,500 and $2,000. Also, there were no more I/O points to use to connect new, additional equipment. The city decided that they wanted a new system with an open architecture that was Windows-based and offered flexibility and expansion capabilities.
The greatest challenge in installing the new system was the manpower to get the new system put in. The city needed qualified people to implement a new system for the wastewater treatment facility that would fit into the overall utility design. So the City of Rock Hill hired the company I work for, INTEWORX.NET. We are an integration firm and an AutomationDirect technology provider. We were called in for our recommendations and skills in implementing the new control and monitoring system for the wastewater treatment facility.
I suggested that the city use Think & Do software for the controls, and InduSoft Web Studio to monitor the HMI SCADA part of the new system. These products would offer them the expandability that they needed, and changes would be easy and less expensive to make. Also, with these products, the city would have the added feature of remote monitoring of their equipment with the use of a web browser or mobile PDAs.
We used Think & Do WinPLCs where local control was required. Parts of the plant needed local control for safety reasons, as well as functionality and redundancy purposes. In case the network went down, that part of the plant would continue to run. The rest of the plant only required monitoring. We used AutomationDirect Ethernet 205 remote I/O to gather process information. Think & Do software on a master computer was used to collect remote process values from more than 18 remote Ethernet racks of I/O, and WinPLCs were used to control critical processes and collect information back to the main Think & Do system. By using InduSoft Web Studio, we were able to provide the HMI pages to the whole plant and city over an intranet through a standard web browser. PDAs were provided to the engineers and plant manager for remote monitoring.
With the new system, even the utility's director and assistant director can monitor the facility's pump valve controls, speed controls tank levels and flow, etc. through their web browser or PDAs, without physically being at the facility. They can also remotely control and monitor samplers. Now, the people who need to have an overview of the facilities can check each facility's progress at any given moment, and receive accurate information and status reports.
Employees have found the news system easy to use and understand. There was very little training necessary, and to date, no questions or complaints. The city plans to expand the system into a city-wide control scheme to include all of the city's utility divisions, including electric and fresh water facilities.
Jon White, maintenance superintendent of water and wastewater, says, "We have been happy with the new system's performance, and appreciate the maintenance savings we expect to gain over the years ahead. The system is expected to meet our needs for quite some time, especially because of the increase in I/O points from 1,200 to 6,000. The new system has exceeded expectations."
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