CONSOLIDATION, COMMUNICATION, CONTROL

Gerdau Ameristeel uses some 19 PLCs from about five different vendors (primarily GE and Allen-Bradley). According to Parrotta, problems were arising because of scalability issues. The plant wanted to add additional Wonderware terminals, but 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,” recalls Parrotta. “KEPServerEX helped simplify the task of connecting the Wonderware terminals and providing the right level of connectivity to address those communications needs.”

Prior to figuring out that resolution, the plant’s 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 simply stop communicating to the other clients . . . skipping a scan cycle entirely. KepServerEX solved this problem by centralizing all the communications to one server. “Rather than having five or six clients pulling data from it, which was mostly repetitious, we had one Kepware server and clients pulled from that server,” says Parrotta.

To add to the complexity of the milling 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 the clients directly to 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 Parrotta, since all the physical I/Os are being logged, they can technically re-create anything the operator did via the Wonderware interface. “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 remarks.

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 Parrotta, QMOS receives a schedule from the ERP system that informs QMOS, for example, of sales orders that define what is needed to manufacture. “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 and tracking all the operational parameters that are critical, such as amps, pressures, kilowatt-hours, time start/stop (off events from PLCs via Kepware),” explains Parrotta. “As these events happen, we move the products we are making through one station to the next, triggering and racking PLC events that are all recorded in Kepware. As the events happen, they move from stage A, to B, to C as part of the batch.” All of 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,” continues Parrotta. “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.”