Fail-safe output modules for electronic control systems

In order to obtain a safety electronic control system, a widely used solution is the massive redundancy approach (i.e., duplication, triplication, etc. of the system), which results in very expensive solutions. This paper presents a method tea make the outputs of an electronic control system fail-safe, with a reduced hardware overhead and a reduced cost. The method, based on the use of dynamic logic, is suitable for its implementation in digital electronic control systems and, in particular, in PLCs of low or medium range.