Online Identification Technology
Tai-Ji Online is an MPC identification software package that carries out online identification automatically. Tai-Ji Online is powered by modern identification technology of Tai-Ji Control and connectivity and software infrastructure of Matrikon. Current version of Tai-Ji Online runs on the platform of ProcessDoctor.
After a pre-test of the
unit, the user can use Tai-Ji Online to perform identification test and to identify
process models using the testing data. The identification procedure consists of
1) Configure the plant test. This is to list the MVs, DVs and CVs. The configuration can be automated using a controller configuration file. Test signals will be generated for the given test.
2) Carry out the test by executing the Test module. The Test module implements the move patterns of corresponding test signals. The test is automatic, but the user can always take manual control actions. The test is multivariable meaning that many or all MV’s are moved simultaneously. The test can be in closed-loop operation, meaning that some (sensitive) CV’s can be controlled by PID controllers or by an MPC controller. Any controller (PID, DMCplus, RMPCT,…) can be used during a Tai-Ji Online test and correlated MV moves are no problem for the technology.
After some time, the Model module will carry out model identification and
validation automatically. Based on the validation result, test signals will be
modified (automatically) and used in the Test module for improving the ongoing
Model identification are scheduled for one to few hours so that fresh models
are obtained automatically at the scheduled interval. Model identification can
also be started manually any time by one mouse click.
Model identification are scheduled for one to few hours so that fresh models are obtained automatically at the scheduled interval. Model identification can also be started manually any time by one mouse click.
4) When all the expected models are with good quality (A and B grades) according to model validation, stop the test and load the models to the MPC controller. Controller simulation and commissioning will follow.
The advantages of Tai-Ji ID technology are:
1) Improved model quality. Traditional methods step single variables over a 12 – 24 hour period. Tai Ji Online tests many variables simultaneously, typically over more than 48 hours, resulting in a far richer data set for model identification. Moreover, Tai-Ji Online uses parametric model and maximum likelihood method that delivers most accurate model for the given data.
2) Reduced cost. Test time can be reduced by 70% (to test a crude unit MPC with 20 MV’s will cost 5 days instead of 15 to 20 days) and data analysis and modelling time is reduced by 90%.
3) Reduced disturbance to unit operation during plant tests. This is realized by using closed-loop test. This is operator friendly.
4) Both the identification test and modelling steps are automated. This is control engineer friendly.
Dow Chemical (Netherlands, Germany, USA, Canada), Statoil (Norway, Denmark), SupCon (China), Air Products (USA), ExxonMobil (Worldwide), BP (Netherlands, UK, USA), Valero (USA), IFP (France), TotalFinaElf (France), CITGO (USA), PetroBras (Brazil), Saudi Aramco, Hovensa
Tai-Ji Online Brochure that contains similar information and some windows of the software
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