From a UNIX to a PC Based SCADA System

In order to facilitate the development of supervisory applications involved in slow process control (such as cryogenic control), the LHC/IAS Group (Equipment Controls Group) opted, a few years ago, for an industrial SCADA package which runs on UNIXÒ platforms. However, to reduce costs and following market trends, it has been decided to move over to a PC-based package. Several processes relating to the testing of the prototypes of the LHC magnets are already controlled in this way. However, it was still necessary to provide all the services previously available to the users, for example, data archiving in central databases, real-time access through the Web, automatic GSM calls, etc. This paper presents the advantages and drawbacks of a PC-based package versus a Unix-based system. It also lists the criteria used in the market survey to arrive at the final selection, as well as, the overall architecture, highlighting the developments needed to integrate the package into the global computing environment.