ANSI/ISA-88 standard has gained acceptance in a variety of process industries, in part due to increasingly capable software and ever-faster microprocessors. “The modularity that the standard introduces is a significant benefit, bringing flexibility even to simple systems,” says Tim Matheny, president of ECS Solutions, a certified member of the Control System Integrators Association (CSIA). “It can decouple device-control models from recipe-control models, simplifying reuse of programming codes and templates, adjusting applications, and building new systems. The S88 standard also allows system integrators to develop a wide range of reusable programming modules based on industry standards. It is then possible to select and assemble those modules that match the client’s process structure.”
Southwest Baking LLC, a bread supplier to a large chain of sandwich shops, recently recognized that its PC-based batch system, designed for the dough mixers, was approaching the end of its useful life. The system’s software was obsolete and would have to be replaced. Working with its OEM was not an option, so the baking company contacted Rockwell Automation (RA), supplier of its controller equipment, and ECS Solutions, an RA-authorized process integrator.
Rockwell recommended replacing the existing batch system with FactoryTalk Batch, a more powerful and flexible product that adheres to ISA-88 standard. “Although the Rockwell product is flexible enough to be applied to any process, Southwest Baking was concerned that modification of the OEM controller code that interfaced with FactoryTalk Batch would be a problem,” states Matheny. In addition, the bakery thought a batch management system (BMS) was not necessary because the system being replaced was small. However, Southwest Baking supported the use of leading-edge technology in the facility, stating that “the application of a proven, flexible, off-the-shelf solution that can adapt to our process opens the doors for continuous improvements, even if some benefits are not realized immediately.”
ECS designed and installed the new BMS and made improvements that increased the capacity of the plant over time. Specifically, ECS altered existing logic to use equipment more efficiently, allowing Southwest Baking to reduce batch time and downtime, increasing plant capacity. Dough quality and consistency improved, and changes to recipes no longer required major programming. These improvements were achieved without changes to the process equipment.
Three steps are required when applying FactoryTalk Batch to a new or existing process, according to Matheny. “It is crucial to identify which major pieces of equipment need to be classified as units,” he states. ECS determined that the mix bowl and four hoppers should be so designated. Modifications to the OEM controller code comprised the second step. Here, ECS retained as much of the OEM programming as possible, breaking the OEM code into tasks, each using specific pieces of equipment. Then logic was added to interface each task to FactoryTalk Batch. The last step involved programming how the equipment would be used. In FactoryTalk Batch, recipes are derived from phases. FactoryTalk Batch starts the phase, monitors its state, collects required data and terminates it upon completion. ECS also implemented data collection as part of the new FactoryTalk Batch recipes. This gave the system the flexibility to periodically collect data at the start, during and/or after any phase and allowed Southwest Baking to identify causes of product variations and quickly initiate corrective actions.
The general manager of Southwest Baking saw an advantage in being able to identify a problem as it was occurring and contracted ECS to implement an agile, configurable control system. The company would then be better able to respond to changes in customer requirements because a more agile control system would reduce its costs and downtime. Without any changes to process equipment, ECS installed more efficient controller software and a new operator interface that reduced batch time by an additional 22 percent, improved the quality and consistency of the dough, improved the accuracy of the delivery of ingredients, and reduced downtime from an average of one hour per event to an average of three minutes per event.
According to Matheny, the development of more flexible software running on faster microprocessors is broadening the ability of S88 to manage everything from material handling to plantwide systems. “ISA-88 is a well-accepted batching standard that can now be applied to continuous processes that stop and start sequentially,” he says. Initially considered to be a batching standard, ISA-88 is now identified as a flexible manufacturing standard, used in combination with manufacturing execution systems (MES) and enterprise resource planning (ERP) systems to execute production orders and to manage inventory.