In a multipronged operation Streamworks Group, a South African leader in the field of supply chain management and industrial information technology, was responsible for upgrading different systems at five Sasko mills situated throughout South Africa.
Sasko Milling and Baking Winterton: upgrading an existing PLC and scada system
In a project which took only six weeks to complete, Streamworks upgraded an existing PLC and scada system at the Sasko Milling and Baking Division's mill in Winterton, KwaZulu-Natal, a major producer of maize products. Streamworks added further software to the Modicon PLC software and at the same time upgraded the existing Genesis scada system with a new InTouch scada system - in line with the Sasko Milling and Baking division's policy of standardising on InTouch as its software product of choice.
The resulting system offers increased functionality to allow for changes in the milling process, and also gives Sasko the ongoing support necessary for the smooth running of an operation of this size. Standard systems defined by Sasko are used for the scada, and administrative passwords are required for access control only.
Because the system was upgraded from a DOS-based to a Windows-based system, with all buttons from the original scada still remaining in use, operators and millers alike were familiar with the functionality, and there was no downtime or inconvenience caused by the switchover. In addition, no training whatsoever was required.
The system comprises one workstation and one main Modicon PLC, which are situated in the mill control room and are connected via RS232 and a Modbus driver. InTouch Factory Suite 2000 is used for the operator interface, with Modsoft PLC programming software used for the Modicon PLC.
Sasko Milling and Baking Mobeni: Easy transfer from storage to offloading
Sasko Milling and Baking Mobeni, on the outskirts of Durban, produces white bread and cake flour, industrial flour and bran products, which are stored in large bins prior to distribution either in packets or in bulk offloading bins. In order to allow for a more streamlined transfer of flour from storage to offloading bins (which are situated over a weighbridge) Streamworks upgraded an existing XBT system with an improved, user-friendly InTouch scada.
During the loading process, a bulk transport tanker parks on the weighbridge, which is situated directly beneath a bulk-offloading bin. Once the tanker is correctly positioned, a mere touch of a button on the upgraded scada system ensures that the flour is transferred directly. Colour animation indicates precisely where the flour is at any given moment of the transfer procedure.
One InTouch scada workstation is situated in the main office, near to the weighbridge, and is connected to two double-rack Telemacanique PLCs via a Unitelway DDE driver. A RS485 PLC card is connected to a RS485/RS232 converter, and then into the serial port of the workstation. InTouch provides operator control and user password facilitation. Pre-determined access levels ensure access to relevant functions only.
The project was designed and installed in five months and Streamworks provided full training for all operators, concentrating particularly on the front-end visual displays.
In another successful project which took no longer than five weeks to complete, Streamworks was contracted to upgrade an existing scada system in the mill control room at the Mobeni plant. The objective of the new system is to show visualisation of the mill and also to keep an eye on the entire mill. The immediate benefit to Sasko Milling and Baking Durban of the new system has been shown in the provision of significantly improved faultfinding abilities for maintenance staff at the mill.
The software implemented in the upgrade is InTouch 7.0. The system functions with one workstation located in the mill control room, while two new Telemacanique PLC's were installed by independent contractors to communicate with each other via Fipway protocol. Password control is achieved via InTouch and Windows NT standard security. The system is simple to operate, and full training of all mill and maintenance personnel was achieved in the space of half a day.
Sasko Milling and Baking Bethlehem: Monitoring packaging accuracy
Streamworks was commissioned to perfect a monitoring system to check and record the weight of packets of flour manufactured at the Sasko Milling and Baking facility in Bethlehem. The system consists of six scales and a host computer, with data from scales logged directly into the database via custom designed software. Reports are compiled from the recorded data to evaluate the accuracy of the packing machines and to ensure that the content of each packet complies with the weight specified on the packet.
Microsoft Access forms the basis of the database, amplified by Seagate Crystal Reports. Visual Basic drivers were written to retrieve data from the scales using MSCom functions. The system comprises one workstation situated in the packing control room and other front-end devices include six Adam 4521 RS232 to RS 485 converters and a 2 PCL847B PC card. The scales are located a considerable distance from the control room and each has been connected to an Adam converter which coverts its RS232 signal into RS485 which can run the full distance to the workstation. Streamworks provided full training for end users and an operating manual was drawn up for easy reference to the particular application of this system.
Sasko Milling and Baking Krugersdorp: Increased productivity
Sasko Milling and Baking's mill at Chamdor in Krugersdorp is a major producer of flour, bran and semolina and increased productivity goals made it imperative to upgrade the existing system for the more effective monitoring of various plant areas. Streamworks commissioned a total system in a project lasting seven months, and which demonstrated overwhelming results virtually immediately upon becoming fully operational - with losses in the intake silo having dropped substantially to less than three tons per month.
The basic system comprises six Omron PLCs connected via a Sysmac link PLC network using coaxial cable. The PLC network consists of three PCs - development, I/O server and engineering - which are located in the mill's control room and which link the PLCs and the operator workstation. In addition, an Ethernet network links the operator workstation to the I/O server and development PCs, with the development PC hosting Wonderware InTouch scada and the engineering PC used for the development of the PLC programme as well as for faultfinding PLC related problems.
Five additional workstations located in various areas throughout the mill, including intake, out loading and packing, were upgraded. Software packages which have been incorporated in the new system include Microsoft WindowsNT workstation 4.0, Wonderware InTouch v 7.0, a Streamworks in-house VB Auto Transfer Application as well as a Streamworks Wheat Recipe Application, Microsoft Access 97, Omron Syswin v 3.2 and Klinkmann Omronslk Driver. Scada screens provide an overview of every aspect of the milling procedure, from initial intake to the final transfer of products.
Password and access control ensure that critical operations and data entries can only be performed with correct access levels. The system offers comprehensive reporting across all milling functions. Streamworks provided basic operator training on the new scada, as well as basic onsite PLC training for the Sasko Milling and Baking Division's electricians.
Sasko Milling and Baking Klerksdorp: Reducing downtime
Streamworks was contracted to install a new PLC/scada system at Sasko's maize manufacturing plant in Klerksdorp in order to replace an existing system which had become a burden due to the considerable amount of downtime it was causing. Streamworks was also responsible for the design of the PLC panels.
Most of the existing equipment was refurbished, with older electrical cables and panels removed and replaced. The project took approximately three months to complete and immediate results have shown an improvement in the general operation of the plant as well as a decrease in downtime which has enabled the operation to offer a substantially improved service to its customers.
The system controls and monitors the five different areas of the plant and the software, which has been installed, includes Wonderware InTouch, Microsoft Access and Concept PLC programming software from Modicon. Because the upgrade was done in conjunction with other mills in the Sasko Group, a decision was taken to standardise on Wonderware InTouch as the preferred scada. The Klerksdorp operation opted for Modicon as its PLC of choice.
The entire operation - from the intake of maize to the packing bins - is PLC and scada controlled. A system of audible alarms and coloured lights effectively alerts the system operator to faults, and the scada is password protected to prevent unauthorised users from interfering with normal plant operations. Full InTouch and PLC training was provided to technical staff, both during and after commissioning.
Sasko Milling and Baking, a division of Pioneer Foods, one of South Africa's food manufacturing giants, produces an estimated one-third of the country's gross national bread output every year. A pioneer in many fields, the company has been instrumental in introducing health-oriented innovations - it was the first local producer to introduce vitamin-enriched flour to South African consumers, followed by the innovative manufacture of vitamin A fortified maize meal.
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