HOW DOES a company move from 1980s machine controls to todays latest technology when the firm is in survival mode? I have been in the control industry for 30 years and installed many standalone operator panels with pushbuttons, pilot lights, single-loop controllers and relay systems in customer plants. When I return to these plants, I often see the old systems still operating, many with the original single-loop controllers in manual-mode, or with obsolete hardware that should be replaced.
The simple solution is to install a new control system that relocates the view of the control from the original control panel to a computer-based operator system. The new screens provide the information the operators have always had, but with greater detail about how the plant is operating. Relay cabinets should be replaced with a programmable controller that provides the original interlocking, but also can provide additional protection, troubleshooting and the potential for using advanced controls to improve the process.
New systems offer simple hardware designs, often replacing multiple parts with one component. The ability to troubleshoot the new system can be done with available and proven software, computers and remote diagnostics installed by the original machine manufacturer.
The problem many companies face today is how to justify and pay for the new system, including the cost of removing old outdated systems. I think the justification lies in what capabilities the new control system gives users for the future. These include:
- Centralized View of the Process and Application. A companys operators and managers now can look at the process on one display. This previously required moving up and down a series of operator control panels. The question is: can they now make a more informed decision on the appropriate actions to take, and what costs are saved by avoiding making wrong decisions?
- Improved Machine Protection. A new control system can provide equipment interlocking, as well as monitor multiple events occurring simultaneously, and automatically take the correct action. Consequently, whats the value of protecting the equipment from damage?
- Improved Control Strategies. When new control systems are installed with the help of the machine builder, the latest proven control methods and strategies can revitalize performance. If machine downtime improves by 5%, or chemical additives use is reduced, or machine stability improved, then what are the values of these improvements?
- Interface to other system and sources. When a new system is installed, it can enable internal communication in the plant, or to outside resources such as the original machine vendor. So, what is the value of having an expert look at machine operation and provide support and advice?
- Spare parts and hardware obsolescence. With older systems, many spare parts become obsolete or no longer available. New designs provide single-component technology that replaces the rack, power supply, communication card, and monitor card of older designs. As time passes, inventory will decrease with new control solutions.
- Reduce technical resource needs and equipment downtime. Often a company that installs new controls can reduce resource needs and reeducate its present staff. This can be done by centralizing staff that has multi-plant control system responsibilities. Software programs can provide more information for troubleshooting the cause of interruptions in the machine operation.
- Advanced control. In many cases, advanced, model-predictive control methods can help companies improve quality, lower energy consumption and chemical usage, or increase production from existing equipment. Most advanced control systems are installed in a computer or remote device that communicates via a data highway. When that older control system cant be significantly modified, it has limited or no ability to communicate remotely. How do you adjust that single-loop controller that is operating in manual, or adjust the position of devices that are connected to relays with no communication available?
Companies today need every edge to compete with new and larger plants and processes that provide the same products. They should look to the future benefits of what a new control upgrade solution provides, as well as the initial costs of replacing the existing control equipment. Investing in the latest original equipment manufacturer (OEM) control technology provides opportunities to improve the existing process, performance and hardware availability, and provides operation personnel with an improved view of the operation of existing machinery.
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