Method and system for monitoring and controlling a multi-variable process throughout a plurality of distinct phases of the process
A control of a multi-variable process throughout a plurality of successive, distinct operational phases of the process involves accumulation of sets of values of the process and quality variables (a-j) from previous multiple operations of the process through all its phases, as respective datasets of a historical record. Each dataset includes an identifier (p) of the phase to which it relates. The current values of the applicable process variables (Qa-Qh) during each phase and the phase identifier (p) are indicated on respective axes (Xp,Xa-Xh) of a multi-dimensional display in relation to an operational envelope which defines bounds (UL,LL) for the values of the individual process and quality variables (a-j) relevant to that phase and which is derived from the datasets of the historical record identified with that phase. Changes in the current process variables (Qa-Qh) result in changes of the bounds (UL,LL), and alarm is given when a current value departs from within them. Either manually or automatically correction of an alarm condition is made in accordance with calculation of required change of value of one or more manipulatable process variables (a-c).
1. A method for control of a multi-variable process throughout a plurality of successive, distinct phases of the process, comprising:
(a) the step of accumulating sets of values of process and quality variables from previous multiple operations of the process through all the plurality of phases, the sets of values being accumulated as respective datasets of a historical record, each dataset comprising a plurality of sub-sets of data individually identified respectively with the plurality of phases of the process;
(b) determining which of the plurality of phases is a current phase of the process;
(c) deriving an operational envelope in respect of the current phase, the operational envelope being derived from sub-sets of data which are individually identified in the datasets of the historical record with the current phase;
(d) indicating on respective axes of a multi-dimensional display representation current values of the process variables within the current phase of the process, the current values of the process variables within the current phase being indicated on their respective axes of the multi-dimensional display representation;
(e) indicating the operational envelope against the respective axes of the multi-dimensional display representation to define bounds for values of the process variables within the current phase; and
(f) controlling the process successively through individual phases of the plurality of phases in dependence upon the bounds defined by the operational envelope for values of the process variables within the current phase.
2. The method according to claim 1 , wherein each dataset accumulated in the historical record includes an identifier of the phase to which the dataset relates.
3. The method according to claim 2 , wherein the operational envelope for each individual phase is derived from the datasets of the historical record that include the identifier of that respective phase.
4. The method according to claim 2 , wherein the operational envelope for each individual phase is a respective part of an envelope derived from the datasets of the historical record applicable to one of all the phases and a selection of the phases of the process.
5. The method according to claim 1 , wherein an indication of which phase of the process is current is indicated on a respective axis of the multi-dimensional display representation.
6. The method according to claim 1 , wherein the operational envelope is a convex hull.
7. The method according to claim 1 , wherein the bounds define as between process variables of adjacent ones of the axes, upper and lower limits for the values of those respective process variables.
8. The method according to claim 1 , wherein the axes of the multi-dimensional display representation are parallel to one another.
9. The method according to claim 1 , wherein the axes of the multi-dimensional display representation are spaced from one another angularly.
10. The method according to claim 1 , wherein the operational envelope which defines bounds for the values of the process variables within the current phase also defines bounds for quality variables within the current phase.
11. A system for control of a multi-variable process throughout a plurality of successive, distinct phases of the process, comprising:
(a) means for accumulating sets of values of the process and quality variables from previous multiple operations of the process through all the plurality of phases, the sets of values accumulated being respective datasets of a historical record each dataset comprising plurality of sub-sets of data individually identified respectively with the plurality of phases of the process;
(b) means for determining which of the plurality of phases is a current phase of the process;
(c) means for deriving an operational envelope in respect of the current phase, the operational envelope being derived from sub-sets of data which are individually identified in the datasets of the historical record with the current phase;
(d) means for indicating on respective axes of a multi-dimensional display representation current values of the process variables within the current phase of the process, the current values of the process variables within the current phase being indicated on their respective axes of the multi-dimensional display representation;
(e) means for indicating the operational envelope against the respective axes of the multi-dimensional display representation to define bounds of the current for values of the process variables within the current phase; and
(f) means for controlling the process successively through individual phases of the plurality of phases in dependence upon the bounds defined by the operational envelope for values of the process variables within the current phase.
12. The system according to claim 11 , wherein each dataset accumulated in the historical record includes an identifier of the phase to which the dataset relates.
13. The system according to claim 12 wherein the operational envelope for each individual phase is derived from the datasets of the historical record that include the identifier of that individual phase.
14. The system according to claim 12 , wherein the operational envelope for each individual phase is a respective part of an envelope derived from the datasets of the historical record applicable to one of all the phases and a selection of, the phases of the process.
15. The system according to claim 11 , wherein an indication of which phase of the process is current is indicated on a respective axis of the multi-dimensional display representation.
16. The system according to claim 11 , wherein the operational envelope is a convex hull.
17. The system according to claim 11 , wherein the bounds define as between process variables of adjacent ones of the axes, upper and lower limits for the values of those respective process variables.
18. The system according to claim 11 , wherein the axes of the multi-dimensional display representation are parallel to one another.
19. The system according to claim 11 , wherein the axes of the multi-dimensional display representation are spaced from one another angularly.
20. The system according to claim 11 , wherein the operational envelope which defines bounds for the values of the process variables within the current phase also defines bounds for quality variables within the current phase.