Gerdau Ameristeel is the second largest mini-mill steel producer, and steel recycler in North America, with an annual manufacturing capacity of more than 10 million metric tons of mill finished steel products. Gerdau Ameristeel currently has 11 mini mills running a manufacturing execution system (MES) called QMOS. . While QMOS oversees the management of information to the company’s ERP system, it relies heavily on KepServerEX from Kepware Technologies of Portland, Maine, to manage the myriad of diverse PLCs distributed throughout the mills. Currently there are three additional mills scheduled to come online almost immediately with QMOS and the remaining mills in the near future.
“We have a variety of different PLCs – just about every platform out there - Seimens, Allen Bradley, GE, etc. We’re trying to become more standardized but each mini mill has its own sets of PLCs. The great advantage of using KEPServerEX is that its drivers are able to connect to all the PLCs, regardless of their individual specifications,” said Jason Magill, Application Architect at Gerdau Ameristeel.
In the company’s Jacksonville, Florida mill there are two major operations – the melt shop and rolling mill. There is also a shredder at some locations, which takes large objects – like cars and other large pieces of metal - and shreds them down to be melted in the furnace at the melt shop. To put the mill’s output in a visual perspective, there is approximately one ton of steel in the average car. So basically the Jacksonville operation is melting and rolling about 90 cars per hour or up to 750,000 cars per year.
According to Jarrod Parrotta, Improvement Facilitator at Gerdau Ameristeel Jacksonville plant, the company was utilizing KepServerEX to tie GE PLCs to another PC based automation system. Pleased with KEPServerEX’s operation, when they launched QMOS they expanded their used of Kepware because of its interoperability with their MES, SCADA and PLCs. “When QMOS came into play,” Jarrod said, “we replaced everything with Kepware.”
The Jacksonville rolling mill operation is monitoring approximately 13,000 I/O points and the melt shop has another 10,000 points for a total of 23,000 I/O’s being acquired from PLCs and other smart devices via KEPServerEX. “We’re only about half of where we want to be,” said Jarrod. “Our target is somewhere between 40,000 to 50,000 I/O points.”
Currently in the Jacksonville plant are four Wonderware Terminal Servers – two in the rolling mill and two in the melt shop. They are set up in a redundant configuration and support many distributed thin clients. The thin clients provide an Wonderware InTouch interface for operators on the process network. Future implementation of Wonderware’s FactoryFocus, a read-only version of InTouch, will be used on the corporate network to provide certain executives who have a need for a more granular view of specific operational informationProcess data for both of these systems are collected by KEPServerEX and LinkMaster. Kepware's LinkMaster allows Gerdau staff to easily link data from multiple OPC data sources and procides a simple means of integrating systems from multiple vendors into a single operational solution. In this case the KEPServerEX communiates the data to QMOS and to Factory Focus. “With the current system configuration, I will never have to let anyone through the Firewall. Using the two Kepware servers across the Firewall allows me to provide a security control feature and limit the amount of traffic on the process network,” Jarrod noted.
Gerdau Ameristeel uses some 19 PLCs from about five different PLC vendors (primarily GE and Allen-Bradley). According to Jarrod, problems were arising because of scalability issues. They wanted to add additional Wonderware terminals and were finding the PLC scan rates were being taxed and becoming too slow. “As we added more terminals, some of our processes were nearing the limits of their scan cycles. This was causing us to have data issues. “KEPServerEX helped provide the solution by simplifying the task of connecting the Wonderware terminals and providing the right level of connectivity to address those communications needs.
Prior to figuring out a resolution, our Wonderware clients that were pulling data from the PLCs were running so slow that they weren’t reporting what they needed to report and would just stop communicating to other clients -- skipping an entire communications scan cycle.
KEPServerEX was able to solve the problem by centralizing all the communications to one server. “Rather than having five or six clients pulling data from PLCs, which was mostly repetitious, we had one Kepware server that clients then pulled from,” Jarrod added.
To add to the complexity of the melting and rolling operations, the Jacksonville plant integrated an IBA historian as a separate stand-alone system. “We were gathering data anyway so we decided to create an historical archive. Our historian software pulls client data directly from Kepware. When QMOS was introduced, we already had everything in place so it was just an easy plug and play.”
Currently the Jacksonville operations are logging all their tags. If operators have an issue, they can literally track down the problem to the minutest detail. According to Jarrod, since all the physical I/Os are being logged, they can technically re-create anything the operator did via Wonderware or pushbutton interfaces. “We can trend just about anything and find out if it was a human error or whether it was, for example, a sensor that failed. As long as we have every I/O logged, we can trouble shoot anything,” he said.
QMOS covers the management of the planning, scheduling, and production in the rolling mill and the melt shop. It manages the process from receiving customer orders, creation of production schedules as well as managing the demand for the steel, up to the production of the billets and bundling and packaging and shipment of semi -finished or the finished products to the customers.
According to Jarrod , QMOS receives a schedule from the ERP system. The ERP informs QMOS, for example, of production orders – this is what we need to make.
“QMOS figures out what ingredients are needed for the products. Recipes for those orders reside in both QMOS and Wonderware. QMOS is keeping track of each step in the process. It’s keeping track of all the operational parameters that are critical, for example, amps, pressures, kilowatt hours, time start/stop (off events from PLCs via Kepware). As these events happen, we move the products we are making through one station to the next – triggering and racking PLC events. These are all communicated via Kepware. As the events happen, they move from stage A, to B, to C…as part of the batch. All this is tracked inside the QMOS MES system.
“QMOS is passing data and tags back to Kepware and I’m using that data to trigger Wonderware to auto-load the recipe that is needed. We are moving toward an automatic recipe load. It’s still handled by Wonderware but is getting signals to do so from QMOS through Kepware. We’re pulling data out of the Oracle database on the opposite end within certain parameters and we’re sending those to the KepServerEX to manage the tags to the PLC. In this way, the operators don’t have to manually do it, which eliminates the possibility of human errors,” Jarrod explained.
In the Jacksonville plant, Kepware provides the connectivity between the PLCs, QMOS, Wonderware and IBA historian. Operations are separated into two domains, the plant floor/process side and the corporate side. The ERP resides on the corporate domain and Wonderware, the PLCs, IBA historian reside on the process domain. QMOS and Kepware straddle between the process side and corporate because QMOS via Kepware’s communication delivers data that both corporate and the process people use. There are two redundancy KepServers on the process side and another two KepServers on the corporate side. The plant is running the KepServers as simulation modules where it acts as a client without having any extra drivers or licenses installed.
Two main challenges at the Jacksonville plant, according to Jarrod, were to solve the problems of overtaxing the PLCs and managing the traffic on the network from both the corporate and process domains “With KEPServerEx’s ability to read a variety of PLCs, it helped us overcome those two challenges,” he said.
“We’ve also purchased some of the Kepware redundancy licenses and we’ll be using those for the IBA historian as we only have one IBA server. Redundancy helps us safeguard our operations in the event that a server goes down.” Jarrod added. “The historian creates reports, which operators are consistently analyzing. We view redundancy as high on our list to maintain operational efficiencies.”
The plant uses Kepware’s LinkMaster to connect the KepServers together. “We use LinkMaster to deliver tags from the melt shop to corporate to the rolling mill in order to generate some of the plant energy readings (gas, electric, etc). When we get all the tags in one spot, we run a single consolidated report. Otherwise we would have to run two reports from two different systems and manually add up the numbers. We use Kepware as the vehicle to communicate information to and from the corporate domain to the process domains. LinkMaster enables us to transfer data to and from the melt shop to corporate and back to the rolling mill or in any data configuration we need. The data then goes to the IBA historian for a complete plant utility report. IBA adds tags together, calculates the values and delivers a comprehensive report.
“Kepware is also a critical part of our operations – particularly its ability to manage communications among the array of PLCs that we have distributed throughout our mills. There are lots of different options out there that can satisfy what we need to do but we chose Kepware because Kepware provides the solution that bridges the gap between our MES system and the PLCs to get us the information we need. It enables us quickly add tags on the fly and log them to an historian. We are pleased with the results and will be continuing with Kepware. Actually we plan to standardize all of our plants on Kepware,” Jason noted.