Multi-variable operations
Operation of a multi-variable process involves multidimensional representation of the value (p 1 -p 12 ) of the process variables (P 1 -P 12 ) according to individual coordinate axes, and an operational envelope (UB,LB) derived from a group of sets of values for the process and quality variables (P 1 -P 12 ,Q 1 -Q 2 ) accumulated from multiple, earlier operations of the process, defines an operating zone for the process and quality variables of the process. If the current value (p 7 ) of any process variable (P 7 ) goes outside the envelope, an envelope (UO,LB) for a different, wider grouping of the stored data-sets is displayed at least for the quality variables (Q 1 -Q 2 ). A series of nested envelopes to provide stepwise enlargement of the operating zone may be provided, but non-nested envelopes can be used where there is clustering of acceptable values of process variables of the stored data-sets. The changes to control variables to bring the values of dependent variables within a best operating range can be determined.
1. A method for operating a controllable multi-variable process, wherein a multi-dimensional display representation of the variables according to individual coordinate axes is derived, sets of values of process- and quality-variables accumulated respectively from previous multiple operations of the process are stored, and current values of the process- and quality-variables are indicated on their respective axes in relation selectively to one or other of a plurality of operational envelopes which are each derived from at least some of the accumulated sets of values and which define bounds for the variables and differ from one another in the bounds defined for at least one of the variables, the particular one of the envelopes in relation to which the current values are indicated being dependent on the current value of at least one of the process-variables.
2. A method according to claim 1 wherein the envelopes are nested within one another.
3. A method according to claim 2 wherein the envelopes differ from one another in the bounds defined for the quality-variables.
4. A method according to claim 3 wherein the particular one of the envelopes in relation to which the current values are indicated is changed when the current value of any one of the process-variables moves outside bounds defined for it by that envelope, the change being to another of the envelopes for which the bounds applicable to the quality-variables are wider.
5. A method according to claim 1 wherein the envelopes are not nested within one another.
6. A method according to claim 5 wherein the current values are indicated in relation to one or other of the envelopes in dependence upon whether the current value of an individual process-variable is within a respective part of its range of values.
7. A method according to claim 1 wherein the current value of one or more of the process-variables is changed to bring about a change of envelope by which the lower limiting-bound indicated by it in relation to one or more of the quality-variables is increased whereas the upper limiting-bound indicated by it in relation to another of the quality-variables is decreased.
8. A method for operating a controllable multi-variable process, wherein a multi-dimensional display representation of the variables according to individual coordinate axes is derived, sets of values of process- and quality-variables accumulated respectively from previous multiple operations of the process are stored, first and second operational envelopes for the process- and quality-variables are calculated, the first and second envelopes being related respectively to bounds for the process- and quality-variables of the process and being derived from the accumulated sets of values to the extent that the first envelope is derived from a selected, limited group of the sets and the second envelope is derived from a larger group that includes said limited group, indicating current values of the process- and quality-variables on their respective axes detecting the condition in which any of the current values of the process-variables lie outside the first envelope, and including representation in the display representation of the first or the second operational envelope at least insofar as it relates to the quality-variables, in dependence upon whether or not, respectively, said condition is detected.
9. A method for operating a controllable multi-variable process, wherein a multi-dimensional display representation of the variables according to individual coordinate axes is derived, sets of values of process- and quality-variables accumulated respectively from previous multiple operations of the process are stored, and current values of the process- and quality-variables are indicated on their respective axes in relation to an operational envelope defining bounds for the process- and quality variables, the envelope being calculated from one or another of different parts of a selected group of the accumulated sets of values according to the current value of at least one of the process-variables, the part of the group from which the envelope is calculated comprising sets of the group which, in distinction to the sets of the other part or parts, have values for said one process-variable clustered on the current value thereof.
10. A system for operating a controllable multi-variable process, wherein a multi-dimensional display representation of the variables according to individual coordinate axes is derived, sets of values of process- and quality-variables accumulated respectively from previous multiple operations of the process are stored, and current values of the process- and quality-variables are indicated on their respective axes in relation selectively to one or other of a plurality of operational envelopes which are each derived from at least some of the accumulated sets of values and which define bounds for the variables and differ from one another in the bounds defined for at least one of the variables, the particular one of the envelopes in relation to which the current values are indicated being dependent on the current value of at least one of the process-variables.
11. A system according to claim 10 wherein the envelopes are nested within one another.
12. A system according to claim 11 wherein the envelopes differ from one another in the bounds defined for the quality-variables.
13. A system according to claim 12 wherein the particular one of the envelopes in relation to which the current values are indicated is changed when the current value of any one of the process-variables moves outside bounds defined for it by that envelope, the change being to another of the envelopes for which the bounds applicable to the quality-variables are wider.
14. A system according to claim 10 wherein the envelopes are not nested within one another.
15. A system according to claim 14 wherein the current values are indicated in relation to one or other of the envelopes in dependence upon whether the current value of an individual process-variable is within a respective cluster-zone of its range of values.
16. A system according to claim 10 wherein the current value of one or more of the process-variables is changed to bring about a change of envelope by which the lower limiting-bound indicated by it in relation to one or more of the quality-variables is increased whereas the upper limiting-bound indicated by it in relation to another of the quality-variables is decreased.
17. A system for operating a controllable multi-variable process, wherein a multi-dimensional display representation of the variables according to individual coordinate axes is derived, sets of values of process- and quality-variables accumulated respectively from previous multiple operations of the process are stored, first and second operational envelopes for the process- and quality-variables are calculated, the first and second envelopes being related respectively to bounds for the process- and quality-variables of the process and being derived from the accumulated sets of values to the extent that the first envelope is derived from a selected, limited group of the sets and the second envelope is derived from a larger group that includes said limited group, indicating current values of the process- and quality-variables on their respective axes, detecting the condition in which any of the current values of the process-variables lie outside the first envelope, and including representation in the display representation of the first or the second operational envelope at least insofar as it relates to the quality-variables, in dependence upon whether or not, respectively, said condition is detected.
18. A system for operating a controllable multi-variable process, wherein a multi-dimensional display representation of the variables according to individual coordinate axes is derived, sets of values of process- and quality-variables accumulated respectively from previous multiple operations of the process are stored, and current values of the process- and quality-variables are indicated on their respective axes in relation to an operational envelope defining bounds for the process- and quality variables, the envelope being calculated from one or another of different parts of a selected group of the accumulated sets of values according to the current value of at least one of the process-variables, the part of the group from which the envelope is calculated comprising sets of the group which, in distinction to the sets of the other part or parts, have values for said one process-variable clustered on the current value thereof.