Incorporating high reliability into the design of microprocessor-based instrumentation

The microprocessor has become an important, if not indispensable, component in instrumentation. As on-line, real-time information technology sub-systems or information machines are generally complex, they are particularly susceptible to performance failure. In a noisy environment, many designs allow this performance failure to degenerate into catastrophic failure. Information machines must therefore be made robust enough to continue operating in hostile conditions. The disruptive or interfering types of contamination caused by a hostile environment are classified. Fault tolerant techniques offer a possibility of coping with inoperation by a combination of hardware and software provisions. A ROM based real-time supervision and operating system is described. If the initial design of the microprocessor-based instrumentation incorporates self-correcting software and watchdog hardware, then adequate protection may be provided.