SUCCESS STORIES – IT SOLUTIONS

THE PROBLEM

The Automatic Gauge Control (AGC) is a multivariable control system designed to regulate the thickness of the sheet at the output of a cold rolling mill. Our client had an AGC system in place based on a Hewlett-Packard HP1000 process computer from the 1980s, with control algorithms programmed in Fortran 77.

Due to technological obsolescence and the discontinuation of support from the supplier, it became necessary to perform a reengineering of the AGC, completely replacing the existing system with a new one based on current technologies at the time of its implementation.

THE SOLUTION

The solution designed by Tecnoap focused on a scalable hardware architecture based on a VXI Controller with Intel processors and the Lynx Operating System, a real-time Unix compatible with Posix. Real-time tasks executing control algorithms were timed to run every 2 milliseconds.

For programming the control algorithms, a visual environment for editing functional block diagrams was developed. This environment included a C++ code generator that generated the corresponding code for executing the block diagrams. This code was automatically compiled and downloaded to the controller for execution, making this entire process transparent to the programming user.

As for the control algorithms, they were migrated from Fortran 77 to block diagrams after a reengineering process. The process was tedious and complex, marked by the lack of documentation and riddled with programming flaws and bad practices, which made understanding and comprehending their operation unclear.

Ultimately, thanks to the intervention of experienced engineers in the field of control, programming, and real-time systems, the complete migration and reengineering of these algorithms were successfully achieved.

THE RESULTS

The AGC was installed and put into operation in 30 days, without stopping production and without breaking a single coil of sheet metal. It continued to operate for the next ten years until it was once again replaced due to technological obsolescence by high-speed PLCs.

The cold rolling mill achieved a net productivity of 200 tons per hour, a net efficiency of 102%, and a thickness deviation of no more than 1% at an output speed of 1200 meters per minute.

With the implementation of this solution, the desired level of control was achieved, positively impacting the reduction of times for product identification in warehouses, as well as a significant improvement in the traceability of product movement and distribution until delivery to the end customer.