Technology can be fairly complex and intimidating for some companies, especially if you are contemplating major step changes such as dealing with a merger, moving into a new space, launching a new product, responding to a new release of software/hardware, and so on. Thus, it is sometimes useful to think of technology in simple chunks.
At the grass-roots level, technology is used to monitor and control frontline operations including processes, assets, the environment, labor, and material. This data is then fed to higher-level technology, usually in summary form, such as to your CMMS for asset data, or ERP system for production data.
Monitoring and control devices have been with us for a long time, beginning with completely mechanical programmable logic controllers (PLCs), moving to electronic programmable controllers (PCs), human machine interface (HMI), supervisory control and data acquisition (SCADA), and many other systems depending on the industry and application.
What are monitoring and control systems? The terms “monitoring and control” systems can be defined as follows:
Monitor: Collect data on the status of a given process, asset, and operating environment, including direct and indirect labor and materials (e.g., kilograms of finished product per labor hour, downtime, temperature range on cook cycle).
Control: Regulate whatever measure is being monitored using a feedback loop (e.g., automatic adjustment of temperature of a cook cycle to maintain it within an acceptable range, automatic valve shutoff when a container is filled to correct weight).
Monitoring and control systems range from simple, single-measure monitoring systems, to fully-integrated, multi-measure systems in a lights-out factory environment. These systems are used for online, real-time monitoring and/or control of measures. What gets monitored and controlled can be lumped into the following five major categories:
- Process – a series of actions, events, or conditions to achieve a given end result (e.g., mixing four ingredients, applying heat, and filling containers with the resultant product).
- Environment – the surroundings to a given process or operation (e.g., within a facility, the outside atmosphere, a nearby river).
- Material or product – direct material is something that can be manufactured or refined ultimately for sale. Indirect material is used in support of the process, such as safety gloves worn by operators or spare parts used by maintainers.
- Labor – direct labor is used in the fabrication or refinement process. Indirect labor is expended in support of the process, such as management, accounting clerks, or maintenance staff.
- Equipment or asset – machines or apparatus required for the process (e.g., vessel, cooker, and filler)
Configuring a system
Monitoring and control systems have the following components:
Input devices. There are at least three common types of input devices. They are measurement devices such as a pressure gauge, detection devices such as a photocell, and recognition devices such as a barcode scanner.
Processors. A variety of processors are available to collect and manage the data input including programmable controllers, computers, and proprietary processors that come direct from the equipment manufacturer.
Output devices. There are three possible types of output devices that present the interpreted shop-floor data in a manner that is easy for humans or machines to take appropriate action: a graphic display, a control device such as a reset switch, and a storage device such as a disk or the cloud.
Communications network. To link the various components described above, you need some sort of communications network. As well, the monitoring and control system must be integrated to higher-level systems, such as asset data flowing to the CMMS for input into predictive maintenance, preventive maintenance, labor reporting, spare parts inventory management, and other management applications.
The “monitoring” in monitoring and control
Even a sophisticated control system aided by artificial intelligence requires a back-up monitoring system in the event of system failure, or to allow for experimentation (e.g., product development). As well, monitoring data can be used to justify asset replacement (e.g., monitoring downtime), or as an audit trail for security and maintenance purposes.
Monitoring systems can present data that is both historical and online/real-time, in either hardcopy or electronic form. For the latter, there are various formats used by vendors to display the data, including high-resolution graphics, tabular alarm summaries, trending graphs, dashboards, and standard reports.
Key savings and benefits
Monitoring and control systems are not inexpensive. You can purchase a low-end, turnkey “starter” system for about $10,000 to $50,000 depending on the number and type of input and output points you require. Another variable is the data management requirements, for example, number of screens required, how much and how often data will be collected, reporting features selected (e.g., graphics, alarming, data storage, custom programming, etc.).
Prices escalate quickly to $500,000 and beyond for larger systems with more than 5,000 input/output points. Integrating artificial intelligence into the control logic can also add significantly to the cost. Because the systems are expensive, many companies find cost justification challenging, especially for monitoring systems that depend on humans to act appropriately on the information.
Nonetheless, companies that have made the move to installing or upgrading automated monitoring and/or control systems have claimed substantial savings and benefits as summarized below:
- Greater consistency and quality – This is the single, most important benefit cited by the vast majority of companies.
- Material savings – By improving the accuracy and timeliness of data collection, savings are generated through improved product quality; reduced inventories; improved yield; and reduced scrap, refeed, rework, and product losses.
- Improved asset uptime and availability – Upgrading antiquated monitoring and control equipment with modern technology can lead to ease of troubleshooting, increased reliability of equipment, increased operational capacity, ease of system expansion and change, and ease of use for operators. These factors can, in turn, increase uptime and availability of operating equipment dramatically.
- Reduced human error – Errors in judgement can be expensive and/or dangerous. For example, if something critical fails because of, say, an over-pressured vessel or improper placement by a robot material handler, an automated control system trumps human reaction time. This can save lives and product. As well, good data management systems facilitate root cause analysis.
- Reduced set-ups and changeovers – Continuous processing means increased uptime of equipment, and therefore increased product throughput. It also results in improved labor utilization.
- Greater flexibility – Older systems occupy more valuable space and can be difficult to service. Modern systems are very flexible. Examples of procedures which are simplified are adding or eliminating input and output points, changing control logic, accessing information more quickly using color graphics and other data management features, configuring information to the specific needs of operators and management, servicing the equipment, and communicating with parallel systems and higher-level programs like a CMMS.
- Labor savings – By centralizing and simplifying the monitoring and control functions, the number and idle time of operators can be minimized. Some companies have totally centralized control rooms from which all aspects of operations are monitored and controlled by a minimal number of human operators, still required in case of system failure. Only maintenance personnel are required in the plant itself.
This article is part of our monthly Asset Manager column. Read more from David Berger.