Comparison between commercial and open-source SCADA packages . A case study

SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma) is a new experimental device under development at Consorzio RFX aimed at providing a full-scale ion source prototype for MITICA (Megavolt ITer Injector and Concept Advance), the experiment devoted at supplying a full-scale prototype of the ITER Heating Neutral Beam Injector (HNB). Both experimental devices will be hosted in a new facility known as PRIMA (Padova Research on Injectors Megavolt Accelerated). The correct operation of SPIDER and MITICA will be guaranteed by process automation and plant monitoring that will be implemented using suitable controllers (cycle time greater than 10 ms) in conjunction with appropriate SCADA (Supervisory Control And Data Acquisition) software. This paper presents the tests performed at Consorzio RFX to evaluate commercial and open-source SCADA packages and prepare a technical base for the selection of the SCADA system for SPIDER. Two commercial solutions and two open-source solutions (EPICS and TANGO) were investigated. The typical test-bed was represented by a SCADA system exchanging data with a PLC (Programmable Logic Controller). The case study consisted of: (a) the development of a minimal panel provided with fields for setting parameters and of a trend window; (b) the set-up of two kinds of communication, a direct connection between the SCADA and the PLC and an indirect one by means of an OPC (Object Linking and Embedding for Process Control) server. The communication performance was evaluated measuring the network traffic with a fixed number of data variables exchanged and different polling cycle times. The conclusions show that the final choice of a SCADA package for SPIDER will be between one commercial SCADA and EPICS. This choice will not depend uniquely on the results of the tests, but will be also dictated by the early schedule of the SPIDER operations.