Adjust Quality in Real Time
技术分类:过程与先进控制 作者:Mark T. Hoske 发表时间:2005-12-05
nomic benefits, priorities, and required actions.

Discrete applications have been integrating the concept of in-line quality control, but typically in an open-loop architecture where a system automatically monitors/measures certain variables, stops the line, and alerts an operator to make changes before too much scrap is run. Such systems also might automatically segregate out-of-spec products based on measurements most often provided by high-speed data acquisition and logic linked with machine

vision or other sensors.

In a closed-loop configuration, a logic device would use information analyzed in real time to send a message, actuate a change, and measure again in a self-correcting control/feedback loop.

Until recently, widely available tools didn't have real-time capabilities to allow closed-loop changes in discrete processes, suggests John Leppiaho, senior manager for Proficy software, GE Fanuc Automation. "Most customers don't know why equipment is down. The vision for automatic closed-loop correction is there, but we haven't seen it in practice."

The solution for many would be to better define product specifications and, as processes move away from a quality centerline, depending on the deviation, stop and fix the process. Doing so would improve overall quality and reduce waste, Leppiaho says. "Some product introductions can have 300 quality parameters; any ability to reduce new product cycle time is huge," he explains.

Today's software can offer tremendous advantages by using the S95-based data model, triggering Web reports and alarms from work-in-process issues and down time, allowing management by exception. Customers can create the specs in their data model so that if a process gets out of limits, an alert would be triggered. Such a setup can offer tremendous advantages. "This opportunity is like what HMI offered 10-15 years ago. Consider this HMI/SCADA software for the production level. Productivity gain potential at this level is huge," Leppiaho says.