Wireless instrumentation communication propels plant processes
Using Bluetooth, WirelessHART and cloud connections, plants and facilities are leveraging increased process and diagnostic data to enhance operational efficiency and decrease downtime.
As companies adopt and leverage digitalization, they are implementing smart systems and adding connectivity to data sources to improve operations and empower their workforces. This trend is especially apparent in the field, where process instrumentation and other common devices, like valve actuators, increasingly provide a wealth of diagnostic information.
To make best use of this trend, some plants are implementing programs for communicating diagnostic data to reliability team members, who can use the information to proactively address issues, reduce unscheduled outages, and improve operational performance. For example, an intelligent pressure transmitter can detect early signs of failure, or a smart valve actuator can sense when actuator mechanisms start to stick.
These intelligent devices can make their diagnostic information available to a monitoring host, such as an asset management system (AMS) or a distributed control system (DCS), which in turn can generate alerts informing plant personnel of the issues.
Unfortunately, not all companies have the infrastructure to use this technique. Many modern plants have hundreds or more field devices capable of reporting statuses via the HART communication protocol, but the host systems often do not support HART. Upgrading a DCS to incorporate HART-enabled inputs and outputs (I/O) is a costly undertaking, and DCS diagnostic data collection and analysis tasks require a vast amount of computing power.
Digital transformation can help address these issues, specifically through the adoption of wireless device-level networks, like WirelessHART and Bluetooth. These protocols alleviate the need for signal wiring and provide alternative options to DCS upgrades. Using WirelessHART or Bluetooth, devices can wirelessly transmit multiple process variables and diagnostic data to a wide variety of host systems, providing flexibility for handling instrument data.
Communications can prevent digitalization
The journey for organizational digitalization has many stages, and while many plants operate using some smart instrumentation, most have at least a few traditional instruments that can only communicate via a 4 to 20mA output proportional to the process variable. Therefore, the first step to increasing process efficiency and reducing downtime is equipping the most critical instrumentation with the means to self-assess and report its health condition.
This smart instrumentation alone does not enable plants to achieve these outcomes because they also need a way to collect and process the data. Throughout the process control landscape, many facilities have replaced traditional 4-20mA field instrumentation with HART-enabled wired or wireless smart instruments, but legacy DCS and I/O systems, prevalent throughout the industry, are not capable of handling the new data. As a result, these facilities often end up with orphaned intelligent devices.
For example, consider a leaky control valve. A DCS is commanding the valve closed, sending a zero percent, 4mA analog output control signal, but for some mechanical reason, the valve is unable to fully close. The valve, equipped with an intelligent position-sensing actuator, is aware of this issue, and it generates the appropriate diagnostic data. But this data is stranded on an unconnected island, useless for solving the problem because the DCS cannot read this information via HART or another digital protocol.
For real-time control applications, it may be necessary to upgrade the DCS, or to add new I/O points capable of interpreting multivariable process and diagnostic data. But DCS hardware can be very expensive. Modifications also require extensive checking and validation procedures. Additionally, many DCS software models are licensed based on physical I/O count, introducing further challenges.
For monitoring applications, or for those instances where timing is not critical, wireless communication methods ease the connectivity effort, increase data availability. Wireless communications provide flexibility for processing the data so plant personnel can make informed operational and maintenance decisions.
Circumventing the DCS with Bluetooth
Because intelligent instruments and actuators transmit multiple signals via digital protocols, they can reduce wiring system requirements. And technologies like a WirelessHART/Bluetooth communication adapter create opportunities to liberate this data and create operational value, with minimal installation costs and downtime requirements (Figure 1).
These adapters provide wireless functionality for any instrument that supports HART, without interfering with existing wired analog I/O loops. This empowers plant personnel to unlock multivariable process values and diagnostic data transmission potential among a variety of instruments, without needing to revalidate or modify a legacy DCS.
As a result, plant reliability teams get a network where they can collect instrumentation diagnostic data using any host, like an AMS, and then perform analysis for directing predictive maintenance (PM) efforts. In addition to avoiding the need for costly conduit runs and wiring efforts, this approach eliminates the need to involve DCS systems in data collection for PM and operational optimization strategies.
Asset management systems are not the only host systems for interacting with instrument data. These interfaces also enable technicians to connect with devices through a wireless field communication tablet, or even an app on a smartphone. With the phone’s native Bluetooth turned on, a technician can see a list of all Bluetooth-enabled field devices within range, each distinguished by tag number, and select a device for pairing.
Once connected, an app displays all critical instrument data, like a traditional HART communication interface, but without wires or specialized industrial handheld devices, broadening the list of personnel available for instrument maintenance. Once connected, a technician can monitor instrument health, and with proper authorization can change tags or other configuration parameters if desired. This can all be done without industrial network configuration because the smartphone handles the communications.
While Bluetooth simplifies field maintenance, WirelessHART is often preferred for integrating data from multiple instruments to a central location. For instruments without native WirelessHART capabilities, a dual-purpose communication adapter provides this function as well.
Circumventing the DCS with WirelessHART
After ensuring instruments and actuators speak the right language, plant staff can install WirelessHART edge gateways throughout the facility to pass their data to higher-level host systems, like those used for asset management or enterprise resource planning. They can make device data available to central plant systems via standardized Ethernet and serial protocols, such as Modbus TCP/IP, EtherNet/IP, HART-IP, Modbus RTU, OPC, and others (Figure 2).
Using Bluetooth as a modern tool for field operations with WirelessHART for conventional host system integration provides the means to bypass a DCS, reducing efforts required to obtain smart instrumentation multivariable process value and diagnostic information.
Example: Expand asset communications to the cloud
Within the walls of a facility or the fence line of a plant, field device data is valuable, but by expanding to cloud-based systems, plant personnel unlock greater insight creation potential to further improve asset performance and utilization.
A hazardous waste incineration company leveraged WirelessHART-enabled instruments (Figure 3) and cloud-based analytics to detect and clear pipe scaling in its flue gas denitrification unit. The unit’s heat exchanger experienced severe scaling, reducing its efficiency, and it required extensive periods of downtime to clear the clogs.
By installing additional pressure and temperature transmitters in the unit and integrating the instrument data wirelessly with an edge gateway, the company began recording a vast amount of additional process data, which they passed to cloud-based tools for analysis (Figure 4). Using this instrumentation process, electrical, and diagnostic data, these cloud tools leveraged artificial intelligence and machine learning to accurately predict scaling. Equipped with these insights, facility engineers made small adjustments to the process, greatly reducing the rate of scaling.
The company is expanding cloud capabilities by preparing cloud-based computerized maintenance management system to automatically issue workorders when the analytics system detects process issues. It also will connect to the inventory database, keeping tabs on available spare parts, and will digitally issue orders for those in short supply.
Wireless instruments provide more insights
The ability to capture field data without overhauling existing DCS and I/O systems makes digitalization efforts significantly more affordable and achievable for process plants and facilities. Easy access to instrument data helps increase operational efficiency, while links between operational and business processes in cloud-based analytic tools can help each inform and optimize the other.
Factories of the future will have fewer wire runs, but they will provide more data from wireless instruments, which analytic systems can use to generate insights. This will empower plant personnel to improve plant operations and advance their companies through digital transformation.
Original content can be found at Control Engineering.