Sensor measurement verification in quasi real-time

Abstract

A method and system to perform the verification of measures done by a sensor in quasi real-time. The sensor verification may be implemented at two different levels—a functionality level and a measurement level. At the functionality level, a consistency check of information from different variables may be processed at sensor level depending on the functionality of the physical system being measured. At the measurement level, diagnostics may be performed of the circuits present in the measurement path by specific circuitry and at suitable instants of time to guarantee a Fault Tolerant Time Interval while minimizing sample loss. This may be achieved, at least in part, by increasing the measuring sample rate.

What is claimed is: 
     
         1 . A method for real-time diagnosing of an analog sensor measurement, the method comprising:
 receiving, during a measurement mode, an analog signal indicative of a variable being measured;   converting the analog signal into digital samples measured at an oversampling rate;   pre-processing the digital samples to generate a digital output at a target sampling rate, wherein the oversampling rate is N times the target sampling rate; and   receiving and processing a diagnostic signal, during a diagnostic mode, wherein a last digital output prior to the diagnostic mode is computed from less than N previously measured digital samples.   
     
     
         2 . The method of  claim 1 , wherein a first digital output following the diagnostic mode is computed from less than N previously measured digital samples. 
     
     
         3 . The method of  claim 1 , wherein the digital output is computed as an average value of up to N previously measured digital samples. 
     
     
         4 . The method of  claim 1 , further comprising:
 detecting whether a diagnostic inhibitor is present preventing the diagnostic mode from being initiated; and   initiating the diagnostic mode in an absence of any diagnostic inhibitors.   
     
     
         5 . The method of  claim 4 , wherein the diagnostic mode is initiated, in the absence of any diagnostic inhibitors, in response to the digital samples indicating that measured values of the analog signal are outside a predetermined range of expected values. 
     
     
         6 . The method of  claim 4 , wherein the diagnostic mode is initiated, in the absence of any diagnostic inhibitors, in response to a predetermined time since the last diagnostic mode occurred. 
     
     
         7 . The method of  claim 4 , wherein the variable being measured includes at least one of a battery voltage, a battery current, and a battery temperature. 
     
     
         8 . The method of  claim 7 , wherein the diagnostic inhibitor includes a battery cranking event. 
     
     
         9 . The method of  claim 1 , wherein receiving and processing the diagnostic signal comprises:
 interrupting the measurement mode to initiate the diagnostic mode, wherein no more than one digital output at the target sampling rate is lost to the diagnostic mode.   
     
     
         10 . The method of  claim 9 , wherein a digital output lost during diagnostics is replaced using one of a moving average, a previously known good sample, and an interpolation from previous measures. 
     
     
         11 . The method of  claim 9 , wherein the diagnostic mode is performed using a single sample of the diagnostic signal and a corresponding digital output at the target sampling rate is interpolated from remaining digital samples to prevent any loss of digital outputs at the target sampling rate. 
     
     
         12 . The method of  claim 11 , wherein the corresponding digital output is interpolated from the remaining digital samples using a moving average. 
     
     
         13 . The method of  claim 11 , wherein the corresponding digital output is interpolated from the remaining digital samples using a 3-order spline. 
     
     
         14 . A system for real-time diagnosing of an analog sensor measurement, the system comprising:
 at least one sensor that generates an analog signal indicative of a variable being measured;   an analog-to-digital converter, in communication with the at least one sensor, that converts the analog signal into digital samples measured at an oversampling rate;   a pre-processor that receives the digital samples, during a measurement mode, and generates a digital output at a target sampling rate, wherein the oversampling rate is N times the target sampling rate; and   a controller configured to receive and process a diagnostic signal, during a diagnostic mode, wherein a last digital output prior to the diagnostic mode is computed from less than N previously measured digital samples.   
     
     
         15 . The system of  claim 14 , wherein a first digital output following the diagnostic mode is computed from less than N previously measured digital samples. 
     
     
         16 . The system of  claim 14 , wherein the digital output is computed as an average value of up to N previously measured digital samples. 
     
     
         17 . The system of  claim 14 , wherein the controller is further configured to:
 detect whether a diagnostic inhibitor is present preventing the diagnostic mode from being initiated; and   initiate the diagnostic mode in an absence of any diagnostic inhibitors.   
     
     
         18 . The system of  claim 14 , wherein the controller is further configured to interrupt the measurement mode to initiate the diagnostic mode, wherein no more than one digital output at the target sampling rate is lost to the diagnostic mode. 
     
     
         19 . The system of  claim 18 , wherein the diagnostic mode is performed using a single sample of the diagnostic signal and a corresponding digital output at the target sampling rate is interpolated from remaining digital samples to prevent any loss of digital outputs at the target sampling rate. 
     
     
         20 . The system of  claim 19 , wherein the corresponding digital output is interpolated from the remaining digital samples using one of a moving average and a 3-order spline.