SAC

Conceptual Layout of the Advanced Control System

The platform's control system, as illustrated in the figure, is responsible for decoding the commands given by the operator and acting directly on the "system actuator". On the other hand, the "acquisition system" takes readings of the welding variables and displays them back to the user via the platform interface.

However, the conceptual layout of the SAC, when implemented, takes on formats that are in line with the technology available on the market and in the domain of the LABSOLDA team. Thus, the physical layout of the Advanced Control System has two microcomputers that communicate via their serial ports, responsible for the user interface, signal acquisition and process control. The system's actuator is a welding source.

Physical layout of the Advanced Control System

The use of two CPUs to implement the SAC comes from the fact that two different operating systems are required in the current design of the platform, Ms-Windows and Ms-DOS. As mentioned in chapter 2, despite providing highly functional tools for handling real-time processes, Ms-DOS does not provide a versatile user interface at the levels required by the SAC. On the other hand, Ms-Windows, which provides a highly intuitive operator interface, hinders substantial hardware intervention, which is extremely necessary for the effective control of welding processes.

To this end, the SAC's control structure was implemented on the "Oscilos v 3.1" program, a welding signal acquisition software also developed in the laboratory and entirely structured on the Ms-DOS operating system. In this way, all the intervention logic on the welding source was grouped together in "CPU 2", which controls both the welding processes and the signal acquisition.

The control interface, however, was fully developed on the Ms-Windows platform, "CPU 1", allowing quick access to the variables of each process, as well as making it flexible to draw welding waveforms in the different modalities, using the graphical tools that the platform in question makes available.

The use of two processing units, although inadequate from a functional and even economic point of view, allowed the SAC to be developed in parallel, speeding up progress in its implementation, as well as creating the concept of platform modularity, i.e. the perfect separation between each aspect of the system, control, acquisition, interface and actuation, which makes it able to adapt to new technological concepts.