Optimistic data retrieval in a process control environment
Processing raw data stored in an historian device for determining an amount of products passed through a process element in a process control environment is described. A count value is incremented by a counter at a rate at which products pass through the process element. The count value rolls over to zero when the count value reaches a rollover value R. An historian device periodically receives count value data points from the counter. A deadband value D is set in the historian device for distinguishing between rollovers, resets, and reversals. A client device queries the historian device for an amount of products passed through the process element for a timeframe. The historian device selects a set of count value data points from within the queried timeframe. The historian device determines, based on the selected data points and their quality, an amount of products passed through the process element.
1. A system for retrieving data from a historian comprising:
a historian comprising one or more processors and one or more non-transitory computer readable media, the one or more non-transitory computer readable media having instructions stored thereon that when executed cause the historian to:
receive, by the one or more processors, a counter data points from a counter, the counter configured to keep track of products passing through a process element using the counter data points, the counter including a rollover value;
determine, by the one or more processors, counter data points that fall within a range;
determine, by the one or more processors, counter data points that fall outside the range;
determine, by the one or more processors, counter data points that are null and/or counter data points within the range by not consistent with previous or subsequent counter data points;
set, by the one or more processors, a quality rule mode where the counter data points that fall within a range and the counter data points that are outside the range are used in a calculation, while the counter data points that are null and/or counter data points within the range by not consistent with previous or subsequent counter data points are not used in the calculation; and
determine, by the one or more processors, if a reset, a rollover, or a reversal of the counter has occurred based on the calculation.
2. The system of claim 1 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
identify, by the one or more processors, the counter data points that fall within the range as ‘GOOD’.
3. The system of claim 2 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
identify, by the one or more processors, the counter data points that fall outside the range as ‘DOUBTFUL’.
4. The system of claim 3 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
identify, by the one or more processors, the counter data points that are null and/or the counter data points within the range but not consistent with previous or subsequent counter data points as ‘BAD’.
5. The system of claim 4 ,
wherein if a ‘BAD’ counter data point is encountered, then a last known ‘GOOD’ counter data point or a last known ‘DOUBTFUL’ counter data point is used in the calculation as if the ‘BAD’ counter data point never occurred.
6. The system of claim 4 ,
wherein if a particular counter data point is a ‘BAD’ counter data point and if there are no counter data points prior to a start of a queried timeframe, then the system is configured to use a zero in the calculation as a starting base value for the ‘BAD’ counter data point.
7. The system of claim 6 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
divide, by the one or more processors, the counter data points into multiple time cycles in response to a queried timeframe;
wherein a starting base value for one or more of the multiple time cycles is calculated from a first actual data point in one or more of the multiple time cycles, rather than the zero.
8. A system for retrieving data from a historian comprising:
a historian comprising one or more processors and one or more non-transitory computer readable media, the one or more non-transitory computer readable media having instructions stored thereon that when executed cause the historian to:
receive, by the one or more processors, a counter data points from a counter, the counter configured to keep track of products passing through a process element using the counter data points, the counter including a rollover value;
determine, by the one or more processors, counter data points that fall within a range;
determine, by the one or more processors, counter data points that fall outside the range;
determine, by the one or more processors, counter data points that are null and/or counter data points within the range but not consistent with previous or subsequent counter data points;
set, by the one or more processors, a quality rule mode where the counter data points that fall within a range, the counter data points that are outside the range, and the counter data points that are null and/or counter data points within the range by not consistent with previous or subsequent counter data points are used in a calculation;
determine, by the one or more processors, if a reset, a rollover, or a reversal of the counter has occurred based on the calculation.
9. The system of claim 8 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
determine, by the one or more processors, if a reset has occurred if a first counter data point is greater than a following counter data point and the first counter data point is less than R*(1-D/100) and the following counter data point is less than R*D/100.
10. The system of claim 8 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
determine, by the one or more processors, if a reversal has occurred if a first counter data point is greater than a following counter data point and a difference between the first counter data point and the following counter data point is less than R*D/100.
11. The system of claim 8 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
determine, by the one or more processors, if a rollover has occurred if a first counter data point is greater than a following counter data point and the system has not determined that the reset and the reversal has not occurred.
12. A system for retrieving data from a historian comprising:
a historian comprising one or more processors and one or more non-transitory computer readable media, the one or more non-transitory computer readable media having instructions stored thereon that when executed cause the historian to:
receive, by the one or more processors, a counter data points from a counter, the counter configured to keep track of products passing through a process element using the counter data points, the counter including a rollover value;
determine, by the one or more processors, counter data points that fall within a range;
determine, by the one or more processors, counter data points that fall outside the range;
determine, by the one or more processors, counter data points that are null and/or counter data points within the range but not consistent with previous or subsequent counter data points;
set, by the one or more processors, a quality rule mode where the counter data points that fall within a range and the counter data points that are null and/or counter data points within the range by not consistent with previous or subsequent counter data points are used in a calculation, while the counter data points that are outside the range are not used in the calculation;
determine, by the one or more processors, if a reset, a rollover, or a reversal of the counter has occurred based on the calculation.
13. The system of claim 12 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
replace, by the one or more processors, a last counter data point that is null and/or a last counter data point within the range but not consistent with previous or subsequent counter data points with a last counter data point that fell within the range.
14. The system of claim 13 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
replace, by the one or more processors, the last counter data point that is null and/or the last counter data point within the range but not consistent with previous or subsequent counter data points with a zero if there is no last counter data point that fell within the range.
15. The system of claim 14 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
divide, by the one or more processors, the counter data points into multiple time cycles in response to a queried timeframe;
if there is no last counter data point that fell within the range, and there are no previous counter data points prior to a queried timeframe start, then use the zero as a starting base value in at least one of the multiple time cycles.
16. The system of claim 12 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
replace, by the one or more processors, a last counter data point that is null and/or a last counter data point within the range but not consistent with previous or subsequent counter data points with the last counter data point that fell outside the range.
17. The system of claim 16 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
replace, by the one or more processors, the last counter data point that is null and/or the last counter data point within the range but not consistent with previous or subsequent counter data points with a zero if there is no last counter data point that fell that fell outside the range.
18. The system of claim 17 ,
the one or more non-transitory computer readable media having further instructions stored thereon that when executed cause the historian to:
divide, by the one or more processors, the counter data points into multiple time cycles in response to a queried timeframe;
if there is no last counter data point that fell within the range, and there are no previous counter data points prior to a queried timeframe start, then use the zero as a starting base value in the calculation for at least one of the multiple time cycles.