Article written by Jim Cahill, Riyaz Ali on 10/26/2021 – Read the Original Article
Two posts, Valve Travel Control-Pressure Fallback and More on Digital Valve Controller Travel to Pressure Fallback Mode proved to be very popular with the readers of Emerson Automation Expert blog. These posts, featuring Emerson’s Riyaz Ali shared how the Fisher DVC6200 digital valve controller can detect position feedback problems and automatically revert to current-to-pressure (I/P) transducer mode to keep the valve fully operational.
The information contained in these posts have been formalized into an instruction manual supplement for the DVC6200 HW2 digital valve controller. The supplement, Travel Control/Pressure Fallback Fisher FIELDVUE DVC6200 HW2 Digital Valve Controller opens:
Valve position feedback is very important to control valve performance. The DVC6200 HW2 digital valve controller provides a unique feature to detect position feedback issues and automatically revert from travel control to pressure control (I/P transducer mode) to keep the valve operational. This can help avoid costly unplanned spurious trips that can affect plant operation.
A caveat for the instrument level AD, PD, or ODV is that it: