Staying calm, a year from now too.
A well-tuned control loop does not stay well tuned by itself. Valves wear, measurements drift, the load changes and new products or recipes come along. With a periodic review we look at your control loops again, on the same metrics as during the optimisation, so you see when a loop starts to become restless, before operators notice. For a fixed annual fee.
How the periodic review works
The periodic review follows on from a completed optimisation. We match the form to what suits your organisation and your IT department.
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Measured again, on the same metrics
Once a year is usually enough, but we match the frequency to your process. We review every optimised loop again on deviation from setpoint, oscillation, control activity, overshoot, recovery time and margin to alarm and trip limits, and compare that with the verification measurement.
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On site or remotely
This can be done by visiting again, or remotely via an OPC connection to your DCS or historian. OPC is the open standard industrial systems use to exchange data. We only read the trend data and write nothing back. You see the same data in your own system, so you can always look along. No surprises, everything transparent.
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Adjust where needed
If a loop drifts, we first look for the cause: changed process conditions, a valve that no longer follows cleanly or a measurement that shifts. Only then do we adjust, in the same way as during the optimisation: substantiated, discussed in advance and during normal operation.
What you get
Certainty that your control loops stay calm, even as the process around you changes.
- For each loop a short assessment on the same metrics, next to the figures from the verification measurement.
- A heads-up as soon as a loop starts to become restless, with the likely cause.
- A substantiated adjustment proposal where it makes sense, and no change where it is not needed.
- The same data as we have: you can check every conclusion yourself.
Practical details
- Price
- Fixed annual fee Agreed in advance, based on the number of loops. No surprises.
- Frequency
- Usually annually More often with strongly varying load or recipes.
- Form
- On site or via OPC Matched to what your IT department allows.
- Condition
- After an optimisation The review builds on the metrics and the measurement from that programme.
No optimisation done yet?
The periodic review needs a baseline. That comes from the PID Performance Scan and the verification measurement of the optimisation. Start there; the scan is free.
Further reading
- Article
How do control loops perform in practice? What the research says
Research into hundreds of thousands of PID control loops keeps showing the same picture: a large share is in manual, oscillates or runs into a limit. The figures, the sources and the caveats.
- Case study
NOₓ trim controller, SCR ammonia dosing
A controller that corrected more than 40 times per hour and consistently came out too high. Now closer to the setpoint, with half as much correcting.
Want to hold on to the calm?
Tell us which loops have been optimised and whether an OPC connection to your DCS or historian is possible. We will then propose a form that suits you, for a fixed annual fee. Would you like to know more about how that works first? Much of it is already in the frequently asked questions.