Upgrading Industrial Controls
When does it make sense to invest in an upgrade of an industrial control system? When does it not make sense? This month’s newsletter will provide food for thought on the subject, as every case is unique and many times there is not a clear answer.
Obsolescence: Since the advent of electronics in industrial controls, change has been tremendous. Products being obsoleted for ‘new and improved’ has progressed at such a rapid pace that end-users cannot keep up. Some points concerning obsolescence follow. 1) If the obsolete product has been fairly reliable, delay the upgrade. Purchase spare components of the obsolete system from an authorized repair shop or a used equipment dealer (if you were not lucky enough to stock up prior to obsolescence). Testing components before disaster happens is important when buying used. Many older controllers require programming/diagnostic software that runs on outdated operating systems (i.e. Windows 2000, Windows 95). Keep old computers around that are used to interface with obsolete equipment as the software is usually not available on newer operating systems. Even though the controller may be obsolete, program changes and diagnostic interfacing can still be possible with the right tools. If you have multiple installations of the same machine, consider loading the programs/configurations into the devices before storing. Remember, battery-backed-up memory will have a shelf-life. Finally, some PLC models from the big players like Siemens and GEFanuc were private-labeled items from lesser known control manufacturers. For example, some obsolete Simatic TI systems are still available ‘as new’ from the original manufacturer. So don’t give up right away if the big guys say it is obsolete. 2) Given some of the opportunities that SCADA and HMI can offer a manufacturing operation, sometimes a controls upgrade makes sense in order to capitalize on a more efficient process or more capable auxiliary equipment. Older controls while still adequately controlling the machinery, may not communicate to products like Wonderware or the new PanelView. If you decide to upgrade an old PLC, consider replacing the controller and I/O racks and leave the field wiring and devices intact. This approach can save thousands of dollars yet be very effective. Expensive Spares: Let’s face it; sometimes a system is over-engineered. Maybe a simple VFD would be sufficient where a complicated and expensive servo system is applied. The spindle drives on some CNC machines are a good example. So if the failure rate justifies the retrofit cost, consider upgrading. Or better yet, have the system engineered and sitting on the shelf – ready for quick installation when needed. Standardized Controls Platform: While it is a noble cause, it is extremely hard to accomplish. During the time it takes to upgrade a facility, a new platform may be on the horizon. Although, standardizing on control platforms for new equipment usually makes good sense. Don’t worry so much about standardizing on sensors like proximity, photo electric, or fiber optic as there is enough standardization among the manufacturers. Replacing an Efector proximity sensor with an Omron is usually straight forward.
A newer segment of the Industrial Controls market is Machine-to-Machine devices also known as M2M. According to Wikipedia, ‘Machine to machine (M2M) refers to technologies that allow both wireless and wired systems to communicate with other devices of the same type.’ Cellular M2M products like the Alert+ (from Wortman Controls Inc.) allow machines to communicate status and alarms to off-site maintenance and process personnel via text messages. Ethernet-based M2M applications are very popular, but limited to a hard connection. These applications send machine information via e-mail.