A multiple DSP environment for on-line signature analysis of plant instrumentation

It is shown that a typical multiprocessor architecture with four digital signal processors (DSPs) can be used to identify more than one faulty sensor within the time limits imposed by the response time of the process control loops in which the sensors belong. This is achieved through a heuristic algorithm, running on a host computer and assigning to the four processors in a suboptimal way the algorithms used to detect the faulty sensors. Testing of the heuristic algorithm has been made possible by simulating on a computer the operation of the multiprocessing system. If this system is properly programmed, it can detect faulty sensors in a large number of process control loops before the next update of the output of each control loop occurs. Thus the respective controllers can avoid using the data supplied by the faulty sensor and instead can use a known output signal value which will drive the process to a safe state. The program execution time requirements can be met if the individual program routines are properly allocated to the four processors. A heuristic algorithm has been developed to carry out this allocation