Ensuring Reliable Water Connections in China
Each day, a Chinese river’s raw water is collected, filtered and purified, and then sold to the country’s tap water companies.
A while back, one of those tap water companies began construction of a water factory. Phase I of the project established a SCADA system for the factory consisting of an ABB Modcell Multiloop Controller/Processor communicating with Modbus® and a proprietary network.
Clean water could then be pumped through a series of pipes to supply the daily tap water needs for over 43,000 Shanghai residents.
"When the factory was established, it used a SCADA system only to supervise the working processes without any control functionality,” said the manager at Shanghai Yuandong Science & Technology Ltd. (SYST), the system integrator.
In any water system as complex as this one, the water flow can vary dramatically from hour to hour and day to day, depending on domestic demand cycles and the more unpredictable aspects such as rainfall and storms. This makes it essential that the Master Control System be equipped not only with monitoring capabilities but control as well.
Control Ability
"The second phase of the project planned to add control ability to the plant," the SYST manager said. "But they found it impossible since the substations were communicating as slaves, and thus couldn't exchange data and information between each other. The main problem was that data exchanged between the slaves needed to be accomplished through the master node. As long as a personal computer carried out the master task, we could not count on its performance, steadiness, and security. Use of a PLC instead of the PC was preferred."
In order to add the control needed, SYST added an Allen-Bradley® PLC-5®20E with Ethernet capabilities. However, since the original SCADA system was ABB communicating with Modbus, an interface was needed to allow the Modbus end devices to communicate with the A-B system. The solution SYST found was ProSoft Technology’s Modbus communication module.
Since the module communicates over the backplane, needing only standard ladder programming, it provided highly configurable Modbus Master and Slave capability to the existing A-B PLC.
"It was the first time Shanghai Yuandong Science and Technology had used this particular module," said the ProSoft Regional Sales Manager who worked on the application. "But it certainly wasn't the last. They also installed the module in the control system for the compressors in a major automotive plant. Since the module fits directly into the controller, in both instances, it provided a seamless integration of technologies."
"The Modbus module played an important role in the second phase of this project," said the SYST manager. "Without the ProSoft module, this phase could not have been realized."
When asked what the deciding factors were in choosing the ProSoft module for this project, the SYST general manager noted the solution’s ease of operation and implementation, and the higher profits the new setup helped lead to.
A Unique Partnership
This unique partnership of integrated technologies between Rockwell Automation® and ProSoft Technology has enabled SCADA systems around the world to gather data and control operations in a multitude of plants just like the end user’s.
"The Modbus module was also used at a similar facility elsewhere in China,” the ProSoft sales manager said. "According to Rockwell Automation, the customer needed to collect data from Diris Power Meters, which have embedded Modbus communications. They elected to use the module, which allowed them to collect 30 parameters from the power meters instead of the 3 parameters they would have gotten using Analog I/O. The bottom line is, our interface module made more data available for better control and monitoring."
"We take great pride in our ability to help Rockwell Automation interface with alternate networks," said Doug Sharratt, ProSoft founder, said at the time of this application. "We have been able to provide a number of solutions for the water and wastewater industry in China.”
The seamless integration of Rockwell Automation and ProSoft Technology is helping China realize its goal of enough clean, fresh water for all of its citizens.
Learn more about ProSoft Technology’s solutions for Water and Wastewater applications here.