If you don't currently have and regularly use ...
... a control loop management application, like Control Advisor,
... my question is, why do you live with poor loop performance?
I have seen quick paybacks in most cases,
... and the effort is pretty reasonable.
This is one of the best examples of digital transformation ...
... or a new digital workflow, is enabled by technology,
... to yield results that could not otherwise be achieved.
Control loops are all too often the forgotten work course ...
... in the plant.
When I authored a 200,000 loop survey ...
... across several hundred plants, I found that only a third ...
... of loops perform well while a third of loops were in manual,
... and a third of loops performed so poorly,
... they would be better off in manual.
Some plants may use loop tuning software,
... but most don't use a control loop management application ...
... like Control Advisor.
Keep in mind that the operator doesn't go out into the plant ...
... to change valve positions directly.
They operate the plant by making set point changes ...
... in the DCS.
If the controller performs poorly, the operating point ...
... they're trying to change doesn't react fast enough,
... or sometimes reacts wildly, creating instability.
This impacts the ability of the operator ...
... to operate the plant, especially during an upset ...
... when they need to make quick and reliable changes.
Sometimes when the loop acts wildly, or causes instability ...
... in the plant, the operator will put the loop in manual,
... to hold the process steady.
This is one of the reasons that one third ...
... of all loops are in manual.
The traditional way is to ignore the performance of loops,
... until the operator complains that the process is unstable.
The reason that loops are all too often ignored,
... is that the typical failure mode of a control loop ...
... is in oscillation, or sluggishness.
Either way, it's usually unnoticed by the operator.
They just live with the fact that it takes a long time ...
... to reach the set point, or the set point is hard to hold.
This means that all too often,
... there is excessive variability or poor responsiveness ...
... at the constraints or quality points,
... right where you don't want it.
The cost of poor control in a single plant is often ...
... in the millions of dollars per year, in reduced capacity,
... higher energy consumption, and inconsistent product quality.
If we really look into the response during an upset,
... it's also related to the operator's ability ...
... to safely move the operation to a safe condition.
On the mechanical side, increased wear and tear ...
... on equipment due to high variation, also adds up.
Even if control performance is poor, causing an impact ...
... to production capacity and energy cost,
... the plant continues to run and produce product.
There are so many other issues that need attention ...
... in the plant that are more visible ...
... than poor loop performance.
For this reason, it's often not a big priority ...
... to look at control loops.
Only 10% of plants have adopted ...
... a control loop management practise.
The other 90% seem to be stuck in the way we used to work,
... back in the eighties and nineties,
... when technology wasn't available too easily,
... and systematically measure performance,
... and focus on the biggest payback loops.
The feedback PID loop itself is pretty simple.
There are just three parts to a control loop,
... a transmitter that measures flow, pressure,
... temperature level, a control algorithm, usually PID,
... and a final control element, usually a valve.
The problem is that these loops don't exist in isolation ...
... of each other.
They are integrated with the dynamics of the process.
This means there can be a myriad of problems.
Tuning could be mismatched with the process.
The valve could be sticky, causing an isolation.
Or there could be an interaction that causes several loops ...
... to oscillate.
In order to find the root cause of control loop problems,
... you need to look at several loops together as a system.
Fortunately, Control Advisor makes it easy to do this,
... all while considering the objective of the process.
Pretty consistently, we've seen a three to six month payback,
... with some examples that are even much greater than that.
In some cases, we have a single problem that literally pays ...
... for the lifetime of using Control Advisor multiple times.
This is the so called silver bullet problem.
I have personally worked with dozens of control engineers ...
... in plants, and can attest to the systematic reduction ...
... of variation at key points that add up to significantly ...
... better process performance.
There really is no magic to this,
... just using it a few hours a week, systematically,
... and proactively, is all there is to it.
That's a great thing about using Control Advisor.
Since it focuses the user on the biggest payback loops,
... at any given time, you really only need to spend a few hours ...
... a week, or maybe up to 10 to 20% of a control engineers ...
... are technicians time to get these results.
Once the biggest issues have been addressed,
... it takes even less time to manage ...
... and sustain improved performance.
Absolutely yes.
APC typically manipulates the set points of control loops.
If those loops can't control the operating points well,
... then APC can't do its job either.
When the loops perform poorly, it can even result ...
... in APC acting poorly and ultimately being turned off.
In fact, one of the first tasks during an APC project ...
... is to tune the loops before step testing.
If loops were tuned during commissioning,
... they were tuned for the conditions at commissioning.
Most plants go through numerous changes in rates,
... feed stocks, product mix,
... not to mention process equipment degradation,
... like catalyst, heat exchangers, over its lifetime.
All of these changes in the plant cause changes ...
... in the dynamics of the process.
More often than not, the loops are not retuned ...
... at different stages of these process changes,
... and that results in poor loop performance,
... and excessive process variability.
Control Advisor was initially developed ...
... in the mid nineties.
At this point is very mature and proven.
We are already in our third or fourth generation ...
... of the technology.
The algorithms are sound and effective,
... and we know exactly how to use them.
Not at all, just a couple of days of installation and setup,
... with a couple of days of customization and training,
... and the user is already solving important problems.