Systems and methods for identifying a failure in an analog to digital converter
View Patent ↗The present disclosure provides systems and methods for identifying failures in an analog to digital (A/D) converter. An intelligent electronic device (IED) may monitor a digital output of one or more A/D converters. The IED may determine a slope value limit associated with the A/D converter. The IED may determine an output slope value of the digital output based on a difference of a converter output value measured at a first time and a converter output value measured at a later time. If the determined output slope value exceeds the slope value limit, the IED may identify a failure of the A/D converter. An IED may determine that concurrent failures in multiple, parallel A/D converters are indicative of a problem upstream from the A/D converters.
1. An intelligent electronic device (IED) configured to identify a failure in an analog to digital (A/D) converter, comprising:
a meter configured to
determine a first voltage of an output of a first A/D converter at a first time, t 1 , and
determine a second voltage of the output of the first A/D converter at a second time, t 2 ;
a slope value limit module configured to identify a slope value limit corresponding to a slope of a step response of a filter associated with the A/D converter;
an output slope value module configured to determine an output slope value corresponding to a slope of the output of the first A/D converter based on a difference, d 1 , of the first voltage at the first time, t 1 , and the second voltage at the second time, t 2 ;
a comparator module configured to determine that the output slope value is greater than the slope value limit; and
an error reporting module configured to report a failure of the A/D converter based on the determination that the output slope value is greater than the slope value limit.
2. The IED of claim 1 , wherein the slope value limit corresponding to the slope of the step response of the filter associated with the A/D converter is a maximum slope value.
3. The IED of claim 1 , wherein the slope value limit corresponding to the slope of the step response of the filter associated with the A/D converter comprises a slope value smaller than a maximum slope value.
4. The IED of claim 1 , wherein the slope value limit corresponds to the slope of an input forcing function of the filter associated with the A/D converter, the input forcing function comprising a first step function at the first time t 1 followed by a second step function of opposite sign at the second time t 2 .
5. The IED of claim 1 , wherein the slope value limit corresponds to a slope of an impulse response of a filter associated with the A/D converter.
6. The IED of claim 1 , wherein the slope value limit corresponds to a slope of a plurality of combined impulse responses of at least one filter associated with the A/D converter.
7. The IED of claim 1 , wherein the filter associated with the A/D converter comprises at least one sinc filter.
8. The IED of claim 1 , wherein the filter associated with the A/D converter comprises at least one digital filter.
9. The IED of claim 1 , wherein the filter associated with the A/D converter comprises at least one analog filter.
10. The IED of claim 1 , wherein the slope of the filter step response is defined by samples at a time interval equal to the difference between first time t 1 and second time t 2 .
11. The IED of claim 1 , wherein the slope of the filter step response of the filter associated with the A/D converter is defined by samples at a time interval larger than the difference between first time t 1 and second time t 2 .
12. The IED of claim 1 , wherein the meter comprises at least one digital measurement device.
13. The IED of claim 1 , wherein the output slope value corresponds to a mathematical combination of multiple consecutive output voltages of the first A/D converter t 1 , t 2 , t 3 up to t n , where n is an arbitrarily large integer.
14. The IED of claim 1 , wherein the output slope value corresponds to a magnitude of a combination of the slope of the output of the first A/D converter based on the difference, d 1 , of the first voltage at the first time, t 1 , and the second voltage at the second time, t 2 , and a second slope of the output of the first A/D converter based on a difference, d 2 , of a third voltage at a third time, t 3 , and a fourth voltage at a fourth time, t 4 .
15. The IED of claim 1 , wherein the A/D comprises a delta-sigma A/D converter.
16. The IED of claim 1 , wherein the A/D converter comprises a successive approximation register A/D converter.
17. A non-transitory computer-readable medium having instructions that, when executed by a processor, cause the processor to perform operations for identifying a failure in an analog to digital (A/D) converter, the operations comprising:
determining a first voltage of an output of a first A/D converter at a first time, t 1 ;
determining a second voltage of the output of the first A/D converter at a second time, t 2 ;
identifying a slope value limit corresponding to a slope of a step response of a filter associated with the A/D converter;
determining an output slope value corresponding to a slope of the output of the first A/D converter based on a difference, d 1 , of the first voltage at the first time, t 1 , and the second voltage at the second time, t 2 ;
determining that the output slope value is greater than the slope value limit; and
reporting a failure of the A/D converter based on the determination that the output slope value is greater than the slope value limit.
18. A method for identifying a failure in an analog to digital (A/D) converter, comprising:
determining a first voltage of an output of a first A/D converter at a first time, t 1 ;
determining a second voltage of the output of the first A/D converter at a second time, t 2 ;
identifying a slope value limit corresponding to a slope of a step response of a filter associated with the A/D converter;
determining an output slope value corresponding to a slope of the output of the first A/D converter based on a difference, d 1 , of the first voltage at the first time, t 1 , and the second voltage at the second time, t 2 ;
determining that the output slope value is greater than the slope value limit; and
reporting, via a communication link, a failure of the A/D converter based on the determination that the output slope value is greater than the slope value limit.
19. The method of claim 18 , wherein the slope value limit corresponding to the slope of the step response of the filter associated with the A/D converter comprises a maximum slope value.
20. The method of claim 18 , wherein the slope of the filter step response is defined by samples at a time interval equal to the difference between first time t 1 and second time t 2 .
21. The method of claim 18 , wherein the slope of the filter step response of the filter associated with the A/D converter is defined by samples at a time interval larger than the difference between first time t 1 and second time t 2 .
22. The method of claim 18 , wherein the output slope value corresponds to a magnitude of a combination of the slope of the output of the first A/D converter based on the difference, d 1 , of the of the first voltage at the first time, t 1 , and the second voltage at the second time, t 2 , and a second slope of the output of the first A/D converter based on a difference, d 2 , of a third voltage at a third time, t 3 , and a fourth voltage at a fourth time, t 4 .
23. The method of claim 18 , wherein the A/D comprises a delta-sigma A/D converter.