FROM CONTROL SOFTWARE TO CONTROL SYSTEMS Wojciech Kurek

Why?  Lets assume we have a control system simulation implemented in Matlab,  This system meets the desired specs  What next?

Implementing the control system  We do not want to use Matlab on site, because:  The cost of industrial licence is high  Maintenance of Matlab is expensive and requires a PC class computer on site Reliable continous operation of computational unit is required!

What can we do then?  Take the code and rewrite it in C/C++ or other programming language  Compile the Matlab code using Matlab Compiler and get:  Standalone application  Shared library  C/C++, NET or COM component or Java class

Issues with porting the code  A simple control algorithm (i.e. PI controller) can be easily ported to C/C++ or other  However, we require something more that copying the code; we need to get a robust code  Code that is safeguarded against malformed input data,  Immune to malicious attacks  Reliable  Execution time

Why use Matlab instead of writing the code directly in C/C++  Rapid prototyping environment is needed to test new algorithms  Matlab is very easy to debug  Using rapid prototyping allows us not to consider the data types, hardware limitations, connectivity issues etc.  Rapid prototyping allows us to use simulation models thus reducing the time and cost of developing new control solutions  Next step – hardware-in-the-loop

Storing data  Lest assume that we have all the control software in place; what we need next is monitoring and data logging  A simple SQL database is insufficient as it can be insecure due to  input - output data rates  consistency issues when large amount of data is considered

Using recorded data  Consider a system that has pressure and flow recoded in a database. What potential problems can be encountered?  Missing and/or malformed data due to communication errors  The time instant when the measurement is performed not necessary coincide with each other

Example potential problems with recorded data  We have a monitoring system that checks if pressure and flow relation meets the specified formula  The pressure and flow are measured and recorded in a database with a time stamp correponding to the measurement time instant  Can we use the data directly? Why not?

Things to be considered  Security of systems – i.e. recent SCADA systems hacker attacks  Security of data – frequent backup  Reliability  Communication links usage