John Fuller, Director of Research at Emerson Automation Solutions in Marshalltown, IA, recently published an article in the August 2020 issue of Hydrocarbon Engineering. The article describes how valve sensor data can be used to detect developing problems and avoid unnecessary valve overhauls. The article is titled Ways and Means and is summarized below.
Internet of Things in a Production Environment
The Industrial Internet of Things (IIoT) has taken advantage of inexpensive microprocessors and increasingly prevalent sensors to expose data that was never before available. When the data is properly acted upon, it can increase uptime, improve performance, and provide proactive maintenance. However, that data only has value if it is delivered to the correct person in a useful format.
IIoT is particularly challenging for control valve applications because the experts who can analyze and interpret data are often outside the plant and may not even work for the operating company. Opening a communication channel so data is available offsite can expose the plant control system to external cybersecurity threats.
The only reason to collect data using IIoT is because of its value to the end user, but this same appeal can make data and its source device an attractive target of hackers, requiring the intelligent application of cybersecurity best practices. Before IIoT, data was essentially secured by proximity, and by proprietary hardware and software systems which isolated industrial devices as islands of automation.
The situation is a bit different for control valves because the main threat is not the theft of valve performance data, but rather the possibility of someone using an IIoT digital data link, which can be bidirectional, to take control of a critical valve.
Secure Connectivity
One connectivity option uses specialized hardware to allow the valve data to leave the site securely.
With Emerson’s Secure First Mile, a data diode is used to bypass the security of the layers and transmit data to a higher level (Figure 1). This is typically done with data useful for maintenance and reliability, as opposed to control by the automation system.
Figure 1: A data diode blocks data transmission to a control valve, only allowing it to transmit data, much as an electronic diode allows current flow only in one direction.
In this architecture, a control valve is connected to a field gateway, which is in turn connected to an edge gateway via a data diode. The diode only allows data transmission in one direction, in this case from the valve to the edge gateway. This addresses cybersecurity issues by preventing a hacker from taking control of a critical valve.
For WirelessHART communications, security provisions are extensive, implemented with defense in depth model to controlling access to the wireless network, protecting the wireless network infrastructure, and preserving data confidentiality and integrity.
Creating Value from Smart Sensors Data
Unlike smart homes or cars, where the number of sensors has exploded over the past two decades, the number of valve sensors has remained relatively constant (Figure 2). A valve’s input signal, travel, supply/actuator pressure, and temperature sensors are used for the primary purpose of controlling the valve position more accurately.
Figure 2: Modern control valves contain a number of smart sensors, with the potential to add more.
Value is added when this sensor data can be used to troubleshoot performance problems, and even more value is obtained if the data can be utilized to detect developing issues before they impact plant operations. Positioner sensors can detect and alarm on simple issues like low supply air pressure or high temperature. The positioner microprocessor can capture high speed data on valve position and air actuator pressure in real time and create a valve stroke signature. This information can allow a subject matter expert (SME) to calculate bench set, friction, and available seat force. This information can be used to detect degrading performance before valve operation is directly impacted.
IIoT Connectivity Closes the Gap
IIoT communication channels securely deliver this data to the SME, who uses his or her knowledge and expertise to analyze the live data and predict or troubleshoot issues, and to determine the corrective actions necessary to resolve the problem. This data can be sent to any host system, either on premises or in the cloud, for expert analysis. Storing data in the cloud allows for third-party analysis by valve manufacturer experts, often provided as a connected service.
Conclusion
Smart valves now provide the data required by end user and valve manufacturer SMEs to analyze the operation of in-service valves and predict problems before they escalate into major incidents. End users just need to leverage IIoT to securely transport that data outside of the plant to realize the benefits of their smart valve investments through improvements in valve performance, operation and maintenance.