Industrial wireless monitoring and sensing
Wireless technology is a constantly evolving area, especially for industrial users, which often makes wireless infrastructure deployments in industrial environments difficult. Before taking on such a project, facility operators need to be aware of the challenges from rapid prototyping of wireless sensors in an industrial environment and the best practices for radio frequency (RF) design in complex or harsh RF environments, such as manufacturing, industrial, or power generation facilities.
The business drivers for this type of project can most often be associated with the transition from conditioned-based monitoring to performance-based monitoring. The conditioned-based monitoring approach typically means lack of on-line data to support diagnostics, and poor data alignment (such as with data residing in separate databases). In addition, the data points are usually collected manually, and the lack of continuous data does not allow for complex analytics or modeling.
Implementing wireless sensor sets create benefits across multiple areas. For instance, scarce engineering resources can focus on data analysis rather than data collection from disparate sources and can concentrate on few degrading trends rather than every trend. Maintenance workers can reduce or entirely eliminate selected data collection rounds through placement of wireless monitoring sensors. The need for deep technical capabilities on-site and concerns about inconsistent diagnostic results due to experience levels of individual employees can be greatly reduced.
By leveraging wireless technologies, operators can acquire critical component monitoring data in significantly higher volumes, reduce staff impact of making collection rounds, and focus those resources on data analysis and prognostics of issues. By implementing a wireless infrastructure and using it for the rapid deployment of new sensor types, operators can create significant advances in critical component monitoring.
Clear wireless infrastructure design
A haphazard approach to wireless infrastructure project strategy can create huge cost and end user satisfaction issues. Even with good performance parameters, failure can occur if they are for the wrong application. To design the project for success, start with a solid system integration approach and define the business case and a clear concept of operations (ConOps). At the very least, list and prioritize applications.
The approach, business case, and ConOps should drive technical specification and help manage end-user and client expectations. With this in hand, the throughput needs can be defined. These will affect technical decisions, such as access point density, backhaul infrastructure, switching, power requirements, cable/fiber runs, and facility penetrations, among others.
Next, focus on the RF design process. Major steps in the RF design process should include passive and active surveys. Start with a passive survey for RF data collection, spectrum analysis, building composition analysis, and the outdoor features/topology noted. The deliverable after the passive survey should be the preliminary design. Once complete, all of the data can be imported into the RF modeling software to generate the preliminary model and design.
Once the preliminary design is finalized, the active survey can start at the facility. The active survey should validate the exercise for the preliminary access point placements. Measure the actual signal performance and confirm the final design approach. Once approved, it is critical to work with the plant information technology staff and engineer of record to formulate the build package and for iterative reviews of design during the installation process as issues arise. After commissioning, designers should return to the facility for testing and tweaking of the operational system for optimal performance. This last step is often overlooked but is critical for successful implementation.
Critical infrastructure problem
Critical infrastructures have their own unique monitoring needs that are not being met, but a strategically planned wireless infrastructure deployment approach may help alleviate some challenges. Critical infrastructure systems are increasingly a complex blend of old and new systems with varying tolerances and management requirements. Aging infrastructure is expensive to instrument, monitor, and maintain. Often, this causes accidents. New infrastructure has its own set of issues and can generate an unmanageable “firehose” of uncorrelated data.
To complicate things further, today’s compliance requirements are reactionary and constantly evolving, and the market is flooded with fragmented point solutions. Right now, the industry lacks a clear “systems approach.” Accidents, shutdowns, and cyber attacks can occur with a failure to monitor and act, so a well-developed wireless deployment plan is even more important on a critical infrastructure project.
Pervasive wireless network
Facility operators often face aging, legacy equipment that may be “un-instrumented,” and data acquisition on performance and maintenance may be natively impossible. Being able to retrofit ad hoc instrumentation and communicate to gather data and metrics can allow for better operational monitoring and maintenance planning and reduce downtime. One solution is to develop ad-hoc (off- the-shelf) modules for sensor types (humid, temperature, vibration, pressure) to allow rapid deployment of wireless-based sensors to gather relevant data. This allows ad-hoc, short-term, or emergency surveillance of problem devices. Plus, it allows a modular approach to wireless sensor measurement in an aging facility environment without large-scale digital equipment upgrades.
Beyond the delivery of voice over Internet protocol (VoIP) and mobile worker/data applications, the availability of a pervasive wireless network within the facility allows deployment of low-cost sensors and meters for tactical or short-term operational needs. A “bug-like” approach for the deployment of multi-sensor devices that is specific to the operation’s needs should be used.
For example, if a faulty motor or pump is suspected, a camera, vibration sensor, and hall-effect monitor can be attached to the housing. In today’s market, the sensor takes three minutes to assemble the modules in the “plant shop” and one minute to provision on the network.
Cohesive reference architecture
One of the best ways to avoid wireless technology obsolescence, ensure a long system lifecycle, and maximize system utility is to select and deploy wireless infrastructure in the context of a cohesive reference architecture. A reference architecture’s chief function is to provide a baseline roadmap related to interfaces and capabilities of related technology systems and business processes for legacy and planning perspectives. Investing the energy and effort in development of a well-thought-out reference architecture provides several key benefits. These include ensuring equipment compatibility, adherence to and compliance with evolving standards across the enterprise, realization of long-term return on investment goals, and optimal planning of capital expenditure spending.
In an industrial setting the major components comprising a reference architecture typically include field instrumentation, communications, storage/analytics, and presentation/visualization. There are dozens, if not hundreds, of field devices that can be connected using one or more wireless technologies. Capturing field devices in the reference architecture provides an easy method for managing the multiple interfaces that need to occur between field and communications devices. Similarly, management of the interfaces between communications networks to the analytics/storage and presentation/visualization layers is also important to capture in a reference architecture. This ensures that higher layer factors including communications protocols, application programming interfaces, interface libraries, and other critical communications functions are well understood and accounted for during the wireless technology selection process.
Although not without challenges, wireless solutions can act as a common enabling technology. They can:
- Provide ubiquitous communications capabilities
- Offer cross-operational value and utility
- Deliver common IP access using standards with robust cyber security
- Reduce lead time and costs associated with wired cabling.
On many projects, doing nothing is not an option, so the wireless solution acts more as a risk management policy. Plus, a strong communications foundation can address many challenges facility operators face during process transformation.
– Douglas Bowers is a senior project manager at SAIC. He has more than 15 years of experience in system integration for communication and network systems, identifying requirements, writing specifications, design, testing, and delivery, including rapid prototyping and development of sensor systems for industrial environments. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, email@example.com.
Bowers presented in a Control Engineering industrial wireless webcast. Learn more at www.controleng.com/webcast.
www.controleng.com/wireless links to related coverage.