Manufacturing air conditioners, whether industrial or consumer units, is a complex process. Casings, condensers, fans, valves, electronic controls, heat dissipaters, and other components all have individual production rates that must correspond and integrate smoothly for the final assembly process. With these production pressures, it''s critical that plant personnel can accurately track and access real-time production information for productivity trends and downtime analysis. If production of one component stalls, it can have an impact on the entire manufacturing process, leading to lower overall productivity and significant coordination problems.
At Trane''s Tyler, TX air conditioner plant, the company wanted to track information on specific machines in its assembly line, giving both plant floor operators and management access to the real-time information. Having this assembly information would allow the company to identify production totals, uptime/downtime, and most importantly, why a machine would fail to work at the optimum level in the first place. Being able to reduce product or service failure rates to a negligible level (roughly 3.4 failures per million opportunities) would mean that Trane had reached Six Sigma status -- a highly coveted quality achievement.
To develop a system that would meet its needs, and to continue to lead the industry in automating its manufacturing processes, Trane decided to install a new control system, as well as software to track information from the controllers and other devices on the assembly line.
That''s a Wrap
Trane decided to focus first on its spine fin wrapping section of the plant -- the component with the most potential to disrupt the entire production process and reduce finished product assembly rates if not running correctly.
"One of our biggest challenges is simply maintaining production levels," said Paul Milwood, senior principal engineer at Trane. "If the spine fin wrappers can''t keep up with the rest of the plant''s production areas, we can''t increase overall production."
Each of Trane''s 60 spine fin wrapper machines is used to continually wrap and glue a .0005 in. x 1 in. band of ribbon around a 3/8 in. pipe that runs up through the center of the wrapping machine. The finished product is a continuous length of pipe with a ribbon "edging" fanning out perpendicular to the pipe (similar to the fanned edged on a car''s radiator).
Under the previous system, analog counters measured the linear amount of wrapped pipe produced by each spine fin wrapping machine. But this system could be inaccurate and offered no mechanism for measuring or capturing a machine''s uptime and downtime. Each spine fin wrapper was manually controlled with individual control panels and was not integrated with any other wrapping machine.
Trane wanted to collect production data from each spine fin wrapping machine and display it in real time for the machine operators on the plant floor. In addition, the data would appear in HTML format on the company''s secure Intranet, where management could easily access the information and track production progress. To make this as seamless as possible, the machines would have to be integrated.
A Soft Sell
Although Trane''s application could be controlled with standard PLC-based control, Paul Milwood and Tegron, an independent control system design company, agreed that a soft controller, like the Allen-Bradley SoftLogix™, would be a better solution. The PC-based controller takes control functions normally found on a dedicated programmable controller, encapsulates the functions in software, and runs on a commercial operating system. PC-based control provides features and functionality similar to a traditional hard controller, while adding the advantages of the PC environment. More and more control system users, especially in those applications with a high degree of information integration, like Trane, are applying PC-based control solutions since it has the ability to combine HMI, programming, control, and enterprise integration on a single hardware platform.
Allen-Bradley PanelView™ 300 monitors stationed at each bank of wrappers give operators easy access to the system data and operators can monitor the entire system via operator interface stations running the Rockwell Software RSView32™ HMI software.
The Ties That Bind
Steve Voelzke, president of Tegron, and his team designed and installed the system. The SoftLogix controls operations for each of the spine fin wrappers, which are linked together using the Rockwell Automation NetLinx architecture.
The NetLinx™ architecture, consisting of DeviceNet, ControlNet and Ethernet, provides Trane with the ability to configure devices, control and collect information and data efficiently. DeviceNet, which is used for device-level control, is a single cable that connects Trane''s industrial devices, eliminating the need for hardwired I/O. Real-time information is transferred from the devices on the DeviceNet network to the SoftLogix controllers, which in turn track and analyze the data. The robust ControlNet network connects each of these controllers to monitor time-critical applications in the plant. In addition, it configures and collects data without impacting the scheduled control and I/O communications. Ethernet links large amounts of production data to the site management network that controls all the raw materials in and out of the site. The combined use of DeviceNet, ControlNet, and Ethernet networks provides seamless integration throughout the assembly process, and enables operators to view the status of devices and the entire line via the PanelView monitors or remotely via the Internet.
Productivity Is Job # 1
A transaction manager, the Rockwell Software RSSql™ software, acts as an interface between the SoftLogix controller and a Microsoft SQL Server database running in the engineering department. RSSql transfers information from the wrapping machine, such as production totals, uptime, and reason codes, into the database where it can be stored and analyzed. As an extender for RSSql, Rockwell Software RSBizWare Historian™ allows Trane to track and analyze the production data.
Historian provides Trane with an understanding of how each process is performing. The predesigned data models are optimized for time-series data, and Historian supports the analysis of a wide variety of production data by connecting to any database via ODBC. A set of analysis tools makes it easy for companies like Trane to analyze time-series data sets and use the reporting, graphing, and querying functions of the software.
"As a company striving for Six Sigma, we need the production data analysis that RSBizWare Historian provides," said Milwood. "It can give us information on machine output in feet per minute, machine downtime statistics, and even reason codes to help us figure out the source of a machine issue."
Running parallel to the controller-RSSql-SQL route is a controller-RSSql-Oracle Web Server route that allows Trane to take the same production information and post it on the company Intranet. From here, managers can access and review the information via the secure Intranet site.
One Cool System
With the new system and the integrated information architecture now in place, Milwood and his team can track production statistics on every spine fin wrapper, allowing them to quickly identify and correct problems that arise. The information not only helps in determining which machines need adjustment, but even why they may have failed in the first place, a big factor in improving overall efficiency, and reaching Six Sigma status. Having this type of information can increase overall efficiency, and keep all the machines running at peak performance.
Information is also available at every level of the plant. Operators can monitor real-time information on displays and HMI stations on the floor, engineers can view and analyze information from the databases, and managers can view and analyze information via the web, wherever they are located. This advanced information sharing helps Trane keep on top of daily changes in the process, and assists them in improving efficiencies on a daily basis.