In many applications, control and on-off valves are subjected to regular position changes and constant contact with process media, causing wear and tear that must be monitored to prevent operational issues.
Control valves are typically operated with a 4-20mA signal sent from a remote automation system, but without valve position feedback, drift from the intended setpoint can occur. On-off valves are simpler to control, being either fully open or fully closed, but they are no less critical in many processes.
Since 1975, valve positioners, and in subsequent decades digital valve controllers, have provided valve monitoring and other functionality, as discussed in our article, titled “Emerson’s Digital Valve Controller Offers Insights into Asset Health, Optimizing Uptime and Performance,” from the October 2023 edition of Automation.com.
History of valve positioners and controllers
Digital valve controllers contain microprocessors, which facilitate diagnostics and communication with external systems. Rather than a mechanical beam, cam, and flapper assembly, the microprocessor drives position.
In 1975, The Fisher™ 3582i became the first pneumatic valve positioner, providing valve stem travel feedback to match the setpoint more closely. Then, in 1994, the Fisher™ FIELDVUE™ DVC5000 was released as the world’s first digital valve controller, providing diagnostics for itself, as well as the valve and actuator on which it was mounted.
The follow-up Fisher™ FIELDVUE™ DVC6000 and Fisher™ FIELDVUE™ DVC6200 controllers made improvements in ease of maintenance, performance, and reliability. The advances in each iteration were significant, but there was still room for further development.
Edge computing innovations
Building on 30 years of field-proven innovation, the new Fisher™ FIELDVUE™ DVC7K digital valve controller provides key data for further improving performance, reliability, and uptime of both on-off and control valves. Continuous onboard analysis identifies issues in real time, generates alerts detailing the problem, and even provides recommended actions—the latter a new and unique feature.
For flexibility, all information is accessible via the controller’s local user interface, through a Bluetooth® wireless technology-enabled device using Emerson Secure Bluetooth®, or remotely through a digital host system. This controller is compatible with all new valve purchases and can also be retrofitted to most existing valve installations.
New possibilities for control valves
Previously, diagnostic data could only be captured during scheduled diagnostic sweeps or when out of service, but now, the DVC7K constantly monitors control valve operation, empowering users to leverage data and develop work practices in ways never possible with other digital valve controllers.
Special features for on-off valves
The DVC7K provides features specially designed for critical on-off valves, including stroke time degradation tracking and partial stroke testing, as well as additional diagnostics.
Along with the added diagnostic data features, the DVC7K also greatly improves reliability as compared to solenoid control, which is often a weak point for these types of applications. Optional built-in position feedback, provided by two limit switches, provides certainty of operation for on/off valves, without the need for additional devices.
New digital valve controllers provide unprecedented monitoring capabilities to ensure critical control and on-off valves are always functioning at their best. By predicting failures well in advance, they also empower plant staff to optimize maintenance operations.
Visit the Digital Valve Controllers section on Emerson.com to know how you can meet your process reliability and performance goals by bringing intelligence to your entire valve assembly.