Multi-tier approach for data acquisition programming in the TJ-II remote participation system

Programming software to setup acquisition channels during device operation has been developed for the TJ-II remote participation system. The software follows a three-tier model. A first tier (client tier) groups client software containing only user interface code. A second tier (middle tier) includes code for authorization, authentication, and query processing. A third tier (data tier) consists of a relational database server for managing configurations. Multi-platform characteristics are provided by web browsers (client tier) and web servers (middle tier). This architecture avoids that data acquisition system controllers provide access control, database support, or graphic user interface resources. Therefore, computation capabilities of these systems can mainly be devoted to data handling. LabView (from National Instruments) has been used as programming language in the acquisition systems. This design allows a very transparent management of signals, independently on hardware modules and systems.