Field devices with self-monitoring capabilities aren’t new. Indeed, the User Association of Automation Technology in Process Industries (NAMUR), Leverkusen, Germany, issued its NE-107 standard on self-monitoring and diagnostics of field devices in 2006. However, significant developments are occurring and vendors are enhancing capabilities in a variety of ways.
For instance, Dietmar Haag, product manager for level management, Endress+Hauser, Maulburg, Germany, notes: “In addition [to meeting the NE-107 standard], we offer plenty of advanced diagnostics to ensure signal quality, measuring performance, and to detect foaming or build-up for better predictive maintenance and process optimization.”
Such capabilities enable effective level measurement despite the tough challenges posed by some applications today. He cites a recent project for a petrochemical customer in the Middle East as typifying these challenges. The company wanted to upgrade its existing automated tank gauging (ATG) system to comply with the latest recommendations of the American Petroleum Institute. This required an independent high-level alarm system to prevent overfilling. However, the system also had to be independent from any device and method used for ATG. The specification required TUV-certified high safety integrity level (SIL-3) level switches based on the vibrating fork principal — together with continuous self-monitoring and diagnosis (Figure 1).
Endress+Hauser’s answer included its failsafe Liquiphant S level switches, and a control cabinet equipped with SIL-3-rated programmable logic controller and inputs/outputs (I/O) as well as graphic and text displays, SIL sounders and beacon lights. A fully-automated proof-testing procedure and maintenance-free instruments contribute to a lower cost of maintenance, too.
Endress+Hauser’s latest innovation is what they call Heartbeat Technology for reliable and flexible proof testing. The hardware and software (details about both remain guarded) are designed to reduce or even eliminate the plant downtime often needed for field-device maintenance and recalibration.
Heartbeat Technology initially is appearing in the company’s new Proline flowmeter platform with the aim of significantly lowering the rates of dangerous undetected failures in accordance with IEC 61508, the functional safety standards of the International Electrotechnical Commission, Geneva, Switzerland. Time-of-flight level instruments will get the technology later this year; it eventually will become a component of all the company’s level-sensing devices.
With the technology, users can initiate reliable, automated test programs without impacting the running process. The in-situ device verification can be activated with the push of a button or click of a mouse from the field network or via secure internet connection if a web server has been integrated. Following activation, the device then performs a self-test that covers all functional areas.
For measurement devices used in SIL-rated systems, Heartbeat Technology also can afford greater flexibility in planning and minimize downtime in proof testing, e.g., letting staff perform more-complex procedures such as instrument calibration only when needed.
The technology also expands diagnosis and monitoring functions such as process and instrument diagnosis in accordance with NE-107 recommendations. These include the generation of clear instructions, plus trend analyses that detect systematic errors and process influences —leading to early identification of changes in device function or the process itself, enabling proactive maintenance.
“The technology offers a device check — a verification — without process interruption and also additional data monitoring which can be used either to optimize the process or for predictive maintenance for the device itself. For customers, it means improved availability and safety, plus access to additional sensor and process information,” explains Haag.
Access Via App
Improved diagnostics also is a key feature of the Vegapuls 64 radar level sensor for liquids. Launched in May by Vega Grieshaber, Schiltach, Germany, the device allows users to access its diagnostics, as well as operational data including measured value, event memory and sensor status display, echo curve and Bluetooth range information with a smartphone or tablet via an app.
The new sensor boasts other innovations designed to ensure longer life with less maintenance than other devices in very harsh services, says the company. For example, its 80-GHz operating frequency is more than triple the 26-GHz widely used in other level sensors. Vega maintains this is ideal for measuring media with poor reflective properties. The higher frequency reportedly eliminates issues due to internal tank installations or build-up, as well as the need for false-signal suppression.
Impact On Control Systems
Meanwhile, the February release of Yokogawa’s Plant Resource Manager (PRM) R3.30 software tool shows how the growth in field-device diagnostic information is influencing technology developments by automation vendors. The new version includes three enhancements specifically aimed at diagnostics: data collection at one-minute intervals; display of individual device icons; and targeted alarm issuance.
“Faster delivery of device diagnostic information enables notification to operators in closer to real-time so they can better identify and handle abnormal situations by both manual and automated means,” says Sugar Land, Texas-based Gene Chen, Yokogawa’s DCS/safety systems product manager, North America. PRM now offers technical enhancements to support HART 7, significantly improving the speed of diagnostic information for HART field devices.
Similarly, faster scan times allow better automated responses. Device diagnostics’ analysis and monitoring can be automated using Centum VP programming or even by Exapilot, Yokogawa’s modular DCS-platform-independent procedural automation application technology.
“Exapilot or other programming can be set to monitor for specific events and then either take automated action or prompt the operator to respond with guidance messages. The guidance messages are actions from established standard operating procedures used to effectively and consistently handle the situation,” he notes.
The second enhancement, the introduction of individual device icons, is designed to make information more intuitive. “Icons work with human physiology and behavior. They allow operators to quickly assess anomalies that exist within a device. The icons and coloring indicate the importance of individual devices that are displayed in the device status window of the navigation screen. Operators can use this information and the self-diagnostic information displayed for the devices to make quick, priority-based responses when device issues occur,” explains Chen.
The new release also allows end users to more easily issue alarms only to operators responsible for the particular device.
In addition, the June 1st launch of the latest version of the company’s Centum VP R6.03 integrated production control system includes major functional enhancements that enable users to smoothly upgrade their remote I/O to make better use of HART 7 and device diagnostic information gathering.
Broader accessibility of information is coming, believes Chen. He foresees the ability to access process and device performance information when you need it no matter where you are — at the plant, at home or traveling.
“We have had smart devices for over 30 years — so diagnostics and networking [are] not new. What is new is pervasive secure networks. Diagnostics, modern pervasive networks with secure network technologies and computing power [are] driving the ability to generate information from the data and make the information pervasive,” he adds.
The rise of the industrial internet of things (IIOT) and Industry 4.0 — as driven by German chemical companies — is the shape of things to come, says Chen. (See: “Put the Internet of Things into Perspective.”)
Seán Ottewell is Chemical Processing's Editor at Large. You can email him at email@example.com.