Valve Health Diagnostics and Tips

Today’s the final day of Emerson Exchange 2017 in Minneapolis. Let’s close down the week of blogging across the Emerson Exchange 365 community with a Meet the Experts panel on valve health tips & tricks.

The panelists include Steve Hagen, Sean Raymond, Ron Hager, Stanley Amirthasamy, and Jordan Mandernach. After the opening introductions, the panel opened it up for questions.

The first question involved the DVC6200 digital valve controller and autocalibration. Steve fielded the question and said while the process is running, you can replace it and run the setup wizard. It will be pretty accurate, but can be finely calibrated when the process is not running.

A question came in about interpreting the valve signature graphs. If you have an as-new or as-rebuilt graph, you can overlay the current valve signature against these baselines to determine differences. It will tell help determine if there might be a problem or not. It won’t exactly point to the problem, but will tell if the valve needs to be serviced.

Jordan provided an update on HART firmware 7. It adds an actuator pressure limit to provide overpressure production. This provides protection from overpressure from a supply pressure regulator failure.

Another addition are soft cutoffs to ramp the travel from the cutoff threshold to the travel stop to ease into the valve seat. Alerts were also streamlined to remove ones that were not as critical in solving issues with the valves. Field diagnostic alerts based on the NE107 standard provides four levels: maintenance required, out of specification, function check—temporary non-valid output signal, failure—non-valid output signal.

For Foundation fieldbus digital valve controllers, DVC6200f, a Golden Dataset is the valve’s signature as collected at the factory (Factory Golden) and optionally again when installed at the customer’s site (Golden). These signatures provide the baseline to compare valve performance against as the valve signature test is rerun. This data is stored in the digital valve controller.

Jordan next discussed partial stroke testing on DVC6200 SIS digital valve controllers. One addition is a solenoid valve test to pulse the solenoid to make sure there is enough pressure drop, but not enough to trip the safety valve. Right now, this is available for only the DVC6200 SIS with 24VDC solenoids.

Another addition is a short duration partial stroke test which immediately recovers the stroke instead of a delay after the initial travel is made. More criteria have been added to detect abnormal conditions, such as travel deviation, pressure threshold, high friction breakout, low-friction breakout, maximum travel exceeded, minimum travel not achieved, valve not seats and solenoid valve failed.

From a software perspective, ValveLink has added concurrency where diagnostics can be run concurrently, up to three tests, on multiple digital valve controllers instead of serially. This reduces the time required to collect diagnostics for the valve.

ValveLink Mobile is available for the AMS Trex device communicator.

The questions came to an end and the session concluded. What valve health and diagnostics questions do you have for these experts?

1 Reply

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