A safety instrumented function (SIF) within a safety instrumented system (SIS) consists of a sensor, logic solver, and final element. As part of the IEC 61511 global safety standard, these elements within the SIF must be tested during the operational phase of the...
digital valve controller
Partial Stroke Test for Final Elements—Diagnostic Coverage Factors
Partial stroke test is one of the viable means to check mechanical integrity of Final Element of Safety Instrumented Function (SIF) loop. Generally, end users struggle on question of credit of PST for improvement in SIL (Safety Integrity Level). IEC 61508 and IEC...
Low-Bleed or Standard Relays for Control Valves?
Happy New Year everyone! I hope your holidays helped to recharge your batteries and get you off to a great start for 2018. I saw this exchange in my email over the holidays about the effects of using low-bleed relays with Fisher DVC6200 digital valve controllers for...
Positioner Pneumatic Pressure Bleed in Throttling Control Valves
With the emphasis on improving energy efficiency and reducing greenhouse gas emissions, process manufacturers have turned to pneumatic low-bleed and zero-bleed valve positioners. Emerson's Riyaz Ali copied me on an email about a recent article that mentioned a...
5 Questions for Digital Valve Controller and Safety Expert Riyaz Ali
Let's continue our 5 Questions for an Emerson Expert podcast series with our guest, Riyaz Ali. You may recall Riyaz from numerous posts about digital valve controllers and final control elements in safety instrumented system applications. He has almost 40 years'...
Reducing Valve-Induced Unplanned Downtime
Valves are the critical components in any process manufacturing and production operation that touches what is being produced. As such, they are subject to wear and tear. An ARC View report, Leveraging IIoT Technologies to Reduce Valve-Related Unplanned Downtime...
Setting Up and Calibrating Valve Positioners
Short videos are great ways to show how to perform an activity, such as calibrating a valve's actuator to move the valve stem based on the 4-20mA signal it receives from the control system. In this under 5-minute "how-to" video, Emerson's Alex Quah Shu Min...
Separate versus Integral Final Element Accessories Questions
A post from a few years ago, Separate Versus Integral Final Element Accessories in Safety Applications, continues to generate some good questions. I thought I'd make these questions and associated answers more visible in today's post. Here's the first question: I...
Positioner-Only Configuration on Digital Valve Controller
I wanted to share a quick question and answer in an email exchange in case you may have a similar question sometime down the road. The original question was: The Project is about installing two manual Fisher control valves but we want to modify it to include obtaining...
Mounting Digital Valve Controller Howto Video
It has been a busy week as many of the experts around Emerson Process Management here in Austin to work on ways to improve their participation in the social channels. I wanted to share a "how to" video, Mounting a Fisher FIELDVUE DVC6200 Digital Valve Controller to a...
Does Flow Loop Make Valve Positioner Unnecessary?
In the Process Control LinkedIn group, a question was asked: Positioners seem very popular now, but most lines with valves have flow meters attached. Won't a flow loop make the positioner redundant? When asked for clarification, the original poster explained: As far...
Automating Manual On-Off Valves
Unless your plant or production facilities was recently built, chances are that your process has a mix of automatic and manual control. A common area for manual control are on-off valves used in many general purpose applications such as tank filling and emptying,...
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