Safety Fuzzy Logic Controller with 2003 architecture implemented in FPGA

The industrial sector requires not only the performance of systems in terms of quality, productivity and reliability, but also in terms of security. The implementation of Fuzzy Logic Controller (FLC) in Field Programmable Gate Array (FPGA) does not allow only the system reliability and reduce the controller conception life cycle, but also ensures a safety integrity level (SIL) which is required by the field of application and related to the control system architecture. Analysis of a safety fuzzy logic controller implemented in FPGA can be performed by different methods that are related to international standards (IEC 61508 [1] and ISA TR 84.0.0.2 [2]). This paper proposes the analysis of a safety fuzzy logic controller implemented in FPGA with 2003 architecture [3] using a qualitative and a quantitative analysis provided by these standards. The quantitative analysis is performed by the calculation of average probability of failure on demand (PFDavg) of safety related system to define its safety integrity level (SIL). The qualitative analysis is based on the Reliability Block Diagram method [4] and [5] and Fault Three Analysis [5] and [6].