Error Detection and Masking Circuit with High Diagnosability for Redundant Sensors

Sensors are essential components in factory automation. Their reliability can be increased by using fault-tolerant architectures such as Triple Modular Redundancy (TMR). Furthermore, error detection and diagnosis can significantly reduce downtime. This paper first proposes an Analog Error Detection and Masking (AEDM) circuit that produces a correct analog reading as long as at least two of the three analog sensors are operational even if the readings are not identical. This circuit operates in the analog domain. It is then combined with a Digital Error Detection and Masking (DEDM) circuit from the literature, and it is proven that the combined mechanism can detect up to one failure while identifying the failure type (sensor failure or Analog to Digital converter (ADC) failure). This mechanism is then slightly adapted by adding two multiplexers to detect up to two failures simultaneously (one sensor and one ADC). Both mechanisms can propagate a correct output to the rest of the system while also identifying the erroneous modules for easier diagnosis and less repair time. The AEDM was successfully simulated on ELDO.