Updating a control system in any application is a daunting task. The cost of engineering, the downtime needed to replace the hardware, and the hours required to organize and assemble the system are high. But there comes a time when the gains realized from modern capabilities developed within the last few years can quickly pay off any initial costs for the upgrade, especially with the technological leaps and bounds made from networking. Concepts such as intelligent preventive maintenance, leveraging IT technologies, and the data-driven world exist to increase revenue and decrease “panic cases” where a situation rapidly spins out of control without someone in the loop.
Some might say these technologies are pushing the operator out of the system, but the reverse is true: The operator is now more informed and more involved than ever. If a control network doesn’t take advantage of these concepts, it could be losing the very competitive advantage that automation was intended to garner.
1. Intelligent preventive maintenance
One of the biggest goals of preventive maintenance is to decrease the amount of “panic cases”—that is, to avoid when a part suddenly fails without any signs prior to the event, causing unscheduled downtime. Not only are these events big stress points for the engineering and maintenance staff, but they also can be more costly to the business than scheduled downtime. Spare parts must be acquired, and the part must be replaced. Sometimes, another part of the system is affected, such as if a surge passed into a particular piece of the control system. This must also be replaced and sometimes reprogrammed. Meanwhile, the rest of the machine or plant that is connected is idle or operating at less than ideal efficiency levels. Intelligent preventive maintenance empowers the system to alert operators and engineers when something is operating beyond its limits, or sometimes just operating differently than it used to.
For example, a motor is operating in a manufacturing line. It usually draws about 5 amps during a given process. Using modern motor managing equipment, the programmable logic controller (PLC) controlling the system is logging the average load during this process. It takes simple logic to program the controller to recognize that over the course of a given period of time, the average load has increased outside of normal levels and is continuing to increase. In this case, the PLC can now take steps to alert the operator to check the motor. If a problem is found, a maintenance cycle can be scheduled to take care of the problem. Without the awareness of the increased levels, over time the motor might have eventually burned out for one reason or another. Since a new motor is ordered, maintenance is scheduled and the operating motor is now being watched more closely for additional failure indications. What could have been an unscheduled panic downtime situation has become a routine maintenance cycle.
2. Leveraging IT technologies
When the industry chose to use Ethernet infrastructure, questions arose about what to do with the IT team in the plant. Some people advocate for the complete division of IT and automation teams. Alternatively, there are those who create teams composed of automation and IT professionals, where the synergies created between the two generate a healthier, more efficient plant. In addition, the IT professionals learn to understand the unique needs of industrial automation, while the automation professionals learn more about networking and how to leverage existing, open and reliable technologies, such as SNMP, to increase the uptime and transparency of their network.
As mentioned, one implementation of the synergies created when IT and automation teams work together is the leveraging of simple network maintenance protocol (SNMP). SNMP was originally designed for the corporate office environment, but because of the architecture, SNMP also lends itself well to industrial and control applications. For example, ever want to monitor the network usage in real time during a particular process? An SNMP-enabled switch and controller can monitor this statistic as part of its code without compromising the real-time properties of the controller. Another implementation might be in a situation where a network component needs to be replaced. The user might interact with an HMI, and the HMI could call the controller to make an SNMP call to find out exactly which port the specified network component is connected to, thereby decreasing the downtime needed to replace the malfunctioning network component.
3. Data-driven world
In today’s data-driven world, plants and automation systems both require and supply more bits and bytes than ever. The use of the database to tie operations all the way from the supply chain to the point-of sale-systems is closing in on universal. It only makes sense that automation should be tying into this system. Between connecting and automating a great deal of data transfers, such as warehousing, supply locations, and offloading from logistics, additional opportunities such as allowing greater visibility into the manufacturing process, unclogging bottlenecks, and determining what equipment requires an upgrade are all possible from the high-data throughput control system.
A good example of this seamless movement of data is a plant where the control system for the manufacturing line communicates with the warehousing system, such that the supplies for the manufacturing line are kept in the same warehouse as the finished products. Manufacturing sends the warehousing unit a retrieval command. When the material is delivered, the finished product is taken away. Supplies are tracked in real time, failures can be logged during manufacturing, and particular batches can be set aside for quality check. Serialized finished products can be identified down to the exact batch of each component and kept in a database for quality purposes. Logistics can keep track of the day-to-day usage of different components, so that less of each is required in stock.
4. Running fine may not be fine
While a 20-year-old automation system may be running fine, remember that automation was intended to cut down on operator costs and unreliability issues and speed up production or generic task execution. It might be the case that the same 20-year-old system no longer has replacement parts or those parts have become extremely expensive and rare. This compromises reliability and cost. Finding a trained user of the control system might be getting more difficult, and now there are far faster and more efficient systems to do the type of task that the 20-year-old system is doing. The automation system has now lost all major advantages.
The time has come to upgrade. Now is the chance to take advantage of new technologies to tie in the automation system more concretely to the rest of the company’s systems.
- Dan Fenton is product marketing specialist, controls and software, control systems technology, Phoenix Contact USA. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, firstname.lastname@example.org.
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