A hundred years ago, grain was ground into flour using two large stones, called millstones. Since then, the science of milling grain into flour has changed dramatically. Improved equipment, better transportation and particularly computerization have increased milling capacity, allowing mills to expand their production.
Four recently constructed mills in Egypt are a prime example. In an effort to cut costs and produce a higher grade flour, developers have built new, modern mills in the same buildings where giant millstones used to stand.
Old Stones to PLC Control
Danish company, United Milling Systems (UMS), designed and built four new mills in Egypt with Automatic Syd A/S as sub-supplier of the electrical system. Two of the mills, located in Cairo and Ibrahim Awad, Alexandria, were actually converted from old stone mills into modern milling plants. The other two, located in Sowahey and Moharam Bey, Alexandria, were turnkey projects, rehabilitating old roller mills.
UMS installed a total of 34 of the new Satake SRMA roller mills in 3 of the locations. The SRMA not only incorporates the very latest technology, such as fully electronic feeder units and a toothed belt differential drive, but is also simple and user friendly. In the fourth mill, UMS installed a short milling system based on their own developed disc mill. This new solution allows the El Tppin mill, (South Cairo & Giza Flour Mills & Bakery Co.), to produce nearly twice as much flour per day, in a substantially reduced area, compared to a conventional roller mill.
Automatic Syd specializes in the design and manufacture of electrical switchboards, control panels and the development of customized PLC and PC software. It was their job to supply a centralized control station that would allow one miller to monitor the entire plant. UMS and Automatic Syd faced a choice: they could install their own version of a proprietary system, running closed applications or, they could opt for an open communication platform.
Ten years ago, proprietary systems were the norm. But companies soon found that these closed systems were, in the long run, user unfriendly, making the process of integrating new processes and equipment difficult, expensive, and time-consuming, requiring diversified skills and tools. Today, these closed systems are slowly being replaced by open communication platforms.
The Modbus protocol is one of these open applications. It has become so popular, that in many instances it is accepted as the defacto industry standard. This was the application chosen for the mills.
Allen-Bradley PLC5 processors were connected to the mill equipment. However, the A-B processors are not inherently Modbus compatible. Therefore, a Modbus interface was needed.
Modbus Interface Needed
Automatic Syd contacted Rockwell Automation-Denmark for a possible solution. They recommended ProSoft Technology's 3100-MCM module. This module acts as a Modbus interface, providing highly configurable Modbus Master and Slave capabilities to Allen-Bradley PLC and SLC applications.
"Quite simply, the ProSoft Modbus communication interface makes it possible for Allen-Bradley platforms to communicate with a multitude of industrial devices," said Doug Sharratt, lead developer for ProSoft Technology. "Because of our partnership with Rockwell Automation, our Modbus module is designed to fit in the A-B rack, allowing all data exchange to occur over the backplane."
The A-B PLC with the ProSoft module installed in the rack, collects the data and displays it on the miller's PC using Allen-Bradley's RSView.
Centralized Control Cuts Costs
"With the ProSoft module," said Arne Sigfredsen of Automatic Syd, "One miller can easily monitor the entire plant and, in case of emergencies, temporarily take over control until another miller has reached the specific machine to solve the problem. This is a cost effective savings, since it takes fewer personnel and you get a lot of information such as alarms, stock levels, motor loads, etc. from the plant."
"The 3100-MCM Modbus module was one of the first products manufactured by ProSoft Technology," said Alain Chevalin, ProSoft's Regional Sales Manager for Europe and the Middle East. "But eleven years after its invention we are still finding new uses for it. Many industrial devices available today have implemented communications using the Modbus protocol. With our communication interfaces, users in a variety of industries are able to gather a great deal of data which can enhance the understanding of the process or, as in the case of these flour mills, allow the system to be controlled more efficiently."
The Alexandria Flour Mills and Bakery Co., located in Ibrahim Awad and Moharam Bey were the first two mills to go on-line in 1998, producing 150 tons and 225 tons of flour per day. A third, located in Sowahey began operating in December of 1999, also producing 225 tons of flour per day.
The fourth mill is located in El Tppin in Cairo. This new disc mill solution allows the El Tppin mill to produce 450 tons of flour per day. The El Tppin mill has been operating successfully since May of 2000.
United Milling Systems
Accomplishing the task of building modern flour mills where millstones used to stand is a complex undertaking. It takes the combined efforts of a number of companies, all working together in their area of expertise.
It was nothing new for United Milling Systems to receive the contract to convert old stone and roller mills into modern milling plants. The Danish firm is considered an expert engineering company, pioneering the development of many modern milling techniques. Working with internationally renowned scientists, UMS is continually updating their product development and process optimization, developing many of their own patents.
Since they supply complete turnkey milling plants and processing lines, they sub-contracted Automatic Syd A/S, also a Danish company, to supply the electrical needs for the four mills.
One of Automatic Syd's tasks required that all of the roller mills (in some cases for as many as 30 roller mills) in each plant be connected to a centralized control panel.
"Every mill has a keypad, where the miller can take over the control of the mill in emergencies," said Arne Sigfredsen of Automatic Syd. "But some of the mills have 30 roller mills, and without centralized control, it is impossible to monitor all roller mills."
In order to incorporate the most modern equipment and processes available, UMS and Automatic Syd chose Allen-Bradley hardware because of its nationally recognized name brand and the availability of future product support. The Modbus protocol was chosen because of its 'open' communication, making future expansion and change easy and cost effective.
Making It Happen
ProSoft Technology, Inc.
Integrating multiple applications was exactly what was needed for the Egytian flour mills, since the specifications called for the Modbus protocol. That was where ProSoft Technology stepped in.
"One of the things we pride ourselves in is our ability to fit our products to a particular application and, when needed, to quickly develop solutions based on the market needs and specific customer requests," said Doug Sharratt, President and Lead Developer for ProSoft Technology. "We are a major supplier of protocol emulation modules for the Allen-Bradley family of products."
"What we do may seem like a small part of the big picture," said Alain Chevalin, ProSoft's Regional Sales Manger for Europe and the Middle East. "But the fact is, our interface modules allow companies like United Milling Systems, Allen-Bradley and Automatic Syd to use the equipment they feel is best suited for the situation without having to worry about specific protocols. If we don't have an application interface that will work for a particular client, we're willing to seriously look at developing one. We view ourselves as a 'market driven company.'"
Rockwell Automation is known worldwide as a recognized leader in industrial automation technology.
"Complete Automation expresses Rockwell Automation's commitment to promise and deliver integrated open solutions, superior value-added services, global supply and local delivery, and world-class components," said Randy Freeman, vice-president of global marketing for Rockwell Automation in a recent interview with Iron & Steel Review.
"The core of this company is great products that differentiate us from many, many other suppliers," said Keith Nosbusch, President of Rockwell Automation Control Systems in an interview for AB Journal in March of last year. "The seamless integration of multiple applications that Rockwell Automation offers lets our manufacturing customers become more flexible, agile, and responsive to the needs of their customers."