Industrial process control system

• US 4,303,973 A
• Filed: 06/22/1979
• Issued: 12/01/1981
• Est. Priority Date: 10/29/1976
• Status: Expired due to Term

• Current Assignee: The Foxboro Company (Schneider Electric SE)
• Original Assignee: The Foxboro Company (Schneider Electric SE)
• Inventors: Williamson, Robert A. Jr., Ford, Roger W.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US06/051,225
• Time in Patent Office: 893 Days
• Field of Search: 340/515, 340/521, 340/525, 340/711, 340/715, 340/722, 340/286 R, 340/150, 340/712, 340/722, 340/753, 364/103, 364/107, 364/120, 364/518, 364/514, 364/200 MS File, 364/900 MS File
• US Class Current: 700/84
• CPC Class Codes: G05B 15/02 electric

Abstract

An industrial process control system for use with complex processes having many variables to be controlled.

The system includes a CRT screen on which any of a series of predetermined displays can be presented to the process operator.

The displays are arranged in hierarchical fashion, from plant summary information down to detailed data for individual process loops.

The operator'"'"'s console includes a variable function keyboard the keys of which perform functions determined by the particular displays being presented on the CRT.

The CRT display includes symbols positionally correlated with the keys and which identify the key functions for the corresponding display.

The operator is enabled to control the display and the process through use of the keyboard controller with the display presentations.

Claims

1. In an industrial process control system for use with complex processes having a large number of conditions the values of which are to be measured and the measurements directed to associated means for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

said loops being organized in groups pertaining to respective process tasks; and

said groups being clustered as distinct areas of the overall plant;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said display device and arranged to be selectively transferred to said display memory to control the display;

a first set of said digital display data serving to present in separate display sectors of said display device summary information concerning respective process areas;

said digital storage memory having further sets of digital display data including sets representing detailed information concerning a corresponding area summarized in a respective one of said sectors of the display produced by the digital data from said first set of said digital data;

said sets of digital display data each also including display data for presenting symbols on said device in predetermined locations to identify the functions of preselected variable-function keys of said keyboard when the complete set of digital display data is presented on said device; and

display transfer means jointly controlled by said pre-selected keys and by the storage in said display memory of any one of said sets of stored digital display data;

said display transfer means being operable by said pre-selected keys, when one of said sets of stored digital display data has been placed in said display memory, to transfer to said display memory a corresponding one of said further sets of stored digital display data in accordance with the function identified by said symbols of the set of display data presented on the display device by said one set of display data.

2. Apparatus as in claim 1, wherein each of said pre-selected keys is operable, when said first set of stored display data is in said display memory, to transfer to said display memory a corresponding one of said further sets of stored display data representing detailed information about a respective process area.

3. Apparatus as in claim 1, wherein one of said pre-selected keys serves a paging function such that when one of a correlated group of said further sets of display data is stored in said display memory, successive operations of said one pre-selected key will transfer, in predetermined sequential order, each of the other sets of said group of sets of data, including return to said one set of data, in a circular fashion.

4. Apparatus as in claim 1, wherein said first set of digital display data comprises data presenting a summary of the alarm status of said process areas.

5. Apparatus as in claim 4, wherein an alarm condition is indicated by a special characterization of the indicia identifying the process area in which an alarm condition has occurred.

6. In an industrial process control system for use with highly complex processes having a large number of conditions the values of which are to be measured and the measurements used for developing corresponding process control signals for elements such as valves and the like;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said device and arranged to be selectively transferred to said display memory to control the display;

said sets of display data being arranged in multiple levels of information comprising at least first, second and third levels;

said first level comprising a first set of display data representing summary information concerning the overall process control system;

said second level comprising a plurality of second sets of display data each representing a more detailed exposition of a corresponding portion of the summary process information in said first level;

said third level comprising a plurality of third sets of display data each representing a still more detailed exposition of a corresponding portion of the process information represented by one of said second sets of display data at said second level;

said keyboard including a group of variable-function keys which perform functions determined by which of said sets of display data is stored in said display memory;

said sets of display data further including symbol display data presenting indicia symbols on said device to identify the functions which will be performed by said variable-function keys if operated while the corresponding display is on the device; and

means under the control of said variable function keys, when any one of said sets of display data of one of said levels is in said display memory, to selectively transfer to said display memory sets of said display data from other of said levels adjacent said one level, as indicated by the symbols presented on the display device by said one set of display data.

7. In an industrial process control system for use with complex processes having a number of conditions the values of which are measured and the measurements used for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

the control system including a plurality of controllers each operable to produce a corresponding control signal for an assigned operating element;

there being at least one digitally-operated slave unit associated with a selected group of said controllers for providing thereto analog set-point signals, and for receiving therefrom analog status signals such as condition measurement values; and

a central processing unit connected to said digital slave unit by a cable providing for serial-pulse digital communication therebetween in both directions;

apparatus comprising;

an operator'"'"'s console at said central processing unit including a display device and a data-entry keyboard;

a digital display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital data defining a corresponding complete display for said device and arranged to be selectively transferred to said digital display memory to control the display;

a first set of said stored digital data serving to present in separate display regions of said device summary information concerning the control status of the process;

said digital storage memory having further sets of digital data each representing detailed information concerning a plurality of said loops;

each of said further sets of digital data incorporating data for presenting alphanumeric characters to provide precise numerical information concerning the control status of the loop including the value of the set point or output of the controller for the loop;

display transfer means selectively controlled by said keyboard to transfer to said display memory any of said sets of stored display data;

said central processing unit including signal-generating means operable by said keyboard when said display device is displaying the detailed information concerning the control status of a particular loop;

said signal-generating means serving to produce and to transmit over said serial-pulse cable to the slave unit for the controller associated with said particular loop, set point or output charge signals for said associated controller;

said particular slave unit being operable to transmit back to said central processing unit signals reflecting the chamber in set-point or output; and

means operable by said central processing unit for altering the stored data of the set of digital data incorporating the detailed information concerning the control status of said particular loop so as to reflect the changed set-point or output data on the display presentation.

8. Apparatus as in claim 7, wherein said signal-generating means comprises means to change said set-point in small incremental steps, to provide the effect of a relatively slow ramp-change of set-point value.

9. Apparatus as in claim 8, including means to effect a relatively rapid ramp-change of said set-point value.

10. Apparatus as in claim 7, wherein said transmitted signals alter the output of a controller in manual state, and alter the set-point of a controller in automatic state.

11. In an industrial process control system for use with complex processes having a number of conditions the values of which are measured and the measurements used for developing corresponding process control signals for elements such as valves and the like, such combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

the control system including a plurality of process controllers each including means operable to produce a corresponding control signal for an assigned operating element, and each being switchable between automatic and manual control status;

there being at least one digitally-operated slave unit associated with a selected group of said controllers and the corresponding process elements for providing thereto analog operating signals including set-point signals and output signals for manual control;

said slave unit also being arranged for receiving from said controllers and/or associated condition sensors analog status signals such as condition measurement values; and

a central processing unit connected to said digital slave unit by a cable providing for serial-pulse digital communication therebetween in both directions;

apparatus comprising;

an operator'"'"'s console at said central processing unit including a display device and a data-entry keyboard;

a digital display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital data defining a corresponding complete display for said device and arranged to be selectively transferred to said digital display memory to control the display;

said sets of digital data including a plurality of sets incorporating loop data for developing on said display indicia indicating whether the loop is on automatic or manual control and for presenting alphanumeric characters providing precise numerical information concerning the control status of the loop including the value of the set-point of the controller for the loop and the output signal to the associated process element;

display transfer means selectively controlled by said keyboard to transfer to said display memory any of said sets of stored display data;

said central processing unit including signal-generating means operable by said keyboard, when said display device is displaying any one of said sets of loop data, to produce and to transmit signals over said serial-pulse cable to the slave unit for the controller associated with the one particular loop;

said signal-generating means serving to develop upon selective operation of said keyboard;

(a) set-point change signals for said associated controller, for the automatic operation thereof, or (b) output signal changes for the associated process element, for manual operation thereof, or (c) command signals for switching the controller between automatic and manual operation;

display data control means operable by said central processing unit for altering the set of loop data stored in said display memory so as to reflect on the display presentation;

(a) changed set-point data, (b) changed output signal data, and (c) change in automatic/manual status.

12. Apparatus as in claim 11, wherein said central processing unit includes means for controlling said display device such that when said loop is on automatic control, the set-point values are distinguished from the rest of the presentation, and when the loop is on manual control, the output values are distinguished from the rest of the presentation, whereby the operator can quickly focus on the relevant data when involved in making a change in set-point or output.

13. Apparatus as in claim 11, wherein said slave unit includes means to transmit to said central processing unit update signals representing:

(a) set-point values;

(b) output-signal data, and (c) automatic/manual status;

said display data control means being responsive to said update signals for showing the actual set-point data, output signal data, and automatic/manual status.

44. Apparatus as in claim 11, including means for controlling said signal-generating means in accordance with said automatic/manual status so that said signal-generating means can send to said slave unit signals altering the set-point data only when the loop is in manual control.

14. In an industrial process control system for use with complex processes having a large number of conditions the values of which are to be measured and the measurements used for developing corresponding process control signals for elements such as valves and the like;

apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display control for said display device adapted to receive digital data for controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding display for said device and arranged to be selectively transferred to said display control to establish the display presented by said device;

a central processing unit supplied with information signals regarding the status of the process and including means for maintaining said sets of digital display data up-to-date for presentation on said device;

said central processing unit being controllable by said keyboard and operable thereby to selectively transfer to said display control any of said sets of digital display data;

said keyboard including a first plurality of variable-function keys located near said display device so the operator can view those keys and the display;

each of said sets of digital display data including data for presenting on said display symbols which are correlated with at least certain of said first plurality of keys, and which provide information indicating the function to be performed by such correlated key when the corresponding set of digital data controls said display; and

means forming part of said central processing unit, and controllable by any one of said certain keys identified by a display currently presented by the display device, for performing the function represented by the respective symbol correlated with such one key.

15. Apparatus as in claim 14, wherein said symbols presented on said display by certain of said sets of display data are correlated to only a selected number of said first plurality of keys less than the total number thereof;

said central processing unit being arranged to effect no function upon the actuation of any of the remaining of said first plurality of keys not identified by said symbols currently presented on said display device.

16. Apparatus as in claim 14, wherein said keys comprise a group of keys which individually are positionally related to respective regions of the display;

said central processing unit being operable, upon actuation of any of said group of keys, to transfer to said display memory a new set of digital display data representing additional information pertaining to the information originally presented in the region of said display positionally related to the actuated key.

17. Apparatus as in claim 16, wherein said group of keys consists of four sets of dual keys spaced along a principal line, with the two keys of each dual set being located adjacent one another on corresponding lines transverse to said principal line, whereby the eight keys of the group correspond positionally to eight regions of said display.

45. Apparatus as in claim 14, wherein said means forming part of said central processing unit includes means responsive to actuation of at least one of said certain keys, when a predetermined set of said digital display data has been transferred to said display control, for transferring a new set of said display data to said display control.

46. Apparatus as in claim 14, wherein said means forming part of said central processing unit includes means responsive to actuation of at least one of said certain keys, when a predetermined set of said digital display data has been transferred to said display control, for altering the magnitude of a control system value displayed on said display device.

47. Apparatus as in claim 46, wherein said value is the set-point of a controller.

48. Apparatus as in claim 46, wherein said value is the output of a controller.

18. In an industrial process control system for use with complex processes having a large number of conditions and means for measuring the values of said conditions and the measurements used for developing corresponding process control signals directed to elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop, said loops arranged in groups pertaining to respective overall plant areas;

apparatus for monitoring an alarm status occurring within any of said control loops, said alarm status arising when any of said measured values exceed preestablished limits, said apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each having a set of digital display data defining a corresponding complete display for said device and arranged to be selectively transferred to said display memory to control the display;

a first set of said digital display data serving to present on said display device summary information concerning the control status of a plurality of said groups;

said storage memory having further sets of digital data each representing detailed information concerning a plurality of said loops;

said stored digital data including data for developing on said display indicia indicating whether an alarm status exists for any of said loops;

display transfer means selectively controlled by said keyboard to transfer to said display memory any of said sets of stored display data including alarm status data associated therewith;

said keyboard being operable, when any of said sets of digital display data is in said display memory, to acknowledge said alarm status and thereby to effect changes in the indicia of at least certain of said displays;

said sets of digital display data being arranged in a hierarchy of information wherein said loop data contains the most detailed exposition of process information;

said acknowledging of said alarm status serving to change indications on said display of said alarm status only at the hierarchical level of information being presented and all those sets of digital display data exposing less detailed process information, preserving changed indications at lower levels of hierarchy for later retrieval upon returning to the lower level from higher levels in either the same area or group or different area or group without losing the location of lower level indications in higher level groups and areas or its status, acknowledged or unacknowledged, at the lower level.

19. Apparatus as in claim 18, including indicator light means adjacent said display and receiving said process loop data, said light means being positionally correlated with summary information when presented with respect to separate plant areas regardless of which of said sets of digital display data is in said display memory;

said light means having two sections per light, one such section responding to any new unacknowledged loop alarm in said area by intermittently lighting in red, and the other indicating the existence of any acknowledged loop alarm for which alarm conditions remain, thereby resulting in constant indication of process alarm conditions and acknowledgement status for the entire process under the direction of the console, regardless of the level of display hierarchy on the display device at any time.

20. Apparatus as in claim 19, wherein said storage memory includes digital data for categorizing between critical and non-critical alarm status, said status being arbitrarily defined for any loop;

said non-critical alarms being capable of being fully acknowledged at said group data hierarchical level;

said critical alarms being fully acknowledged only at the loop hierarchical data level.

21. In an industrial process control system for use with highly complex processes having a large number of conditions the values of which are to be measured and the measurements used for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

said loops being organized in groups pertaining to respective process tasks; and

said groups being arranged as clusters representing respective preassigned areas of the overall plant;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said device and arranged to be selectively transferred to said display memory to control the display;

said sets of display data containing multiple levels of plant information comprising at least first, second and third levels;

a first set of said display data providing said first level of information and serving when transferred to said memory to present on said display device a number of separate information segments pertaining to respective preassigned areas of the plant under control;

each of said information segments including a plurality of separate presentations each representing a corresponding identified process group of the plant area covered by the respective information segment;

means effective while said first set of display data is in said memory to designate visually on said display device any of said information segments when a preestablished characteristic of one of the process groups represented by such information segment has reached a preselected status;

said second level of information comprising a plurality of second sets of display data each representing a more detailed exposition of a corresponding one of the plant area information segments presented in said first level of information and presenting information concerning all of the process groups represented in the corresponding information segment;

means operable by the console operator when said first set of display data is in said memory for transferring to said memory any of said second sets of display data;

said transfer means including means functioning in coordination with the location of said display device of any visually designated information segment to transfer to said memory the particular one of said second sets of display data corresponding to such visually designated information segment;

means effective while any of said second sets of display data is in said memory to designate visually on said display device said one process group for which said preestablished characteristic has reached said preselected status;

said third level of information comprising a plurality of third sets of display data each representing a still more detailed exposition of a respective process group identified in said second sets of display data;

means operable by the console operator when any of said second sets of display data is in said memory for transferring to said memory any of said third sets of display data;

said transfer means including means functioning in coordination with the location on said display device of said visual identification of any particular process group, while any one of said second sets of display data is in said memory, to transfer to said memory the particular one of said third sets of display data representing the visually designated process group;

whereby the process operator is enabled to follow the same technique in processing from said first to said second information level, as in progressing from said second to said third information level, as he seeks to gain more detailed knowledge about said preestablished characteristic.

22. A system as in claim 21, wherein said preestablished characteristic is the alarm status of any of said process groups.

23. A system as in claim 22, wherein said designating means operates by causing a graphic display portion of the corresponding information segment to blink, thereby to attract the operator'"'"'s attention.

24. A system as in claim 21, wherein said transfer means includes a preselected set of manually-operable keys physically arranged in a layout disposition positionally coordinated with respective regions of said display device;

each of said information segments presented in said first set of display data being positioned in a corresponding one of said regions;

each of said preselected keys being operable upon actuation to transfer to said display device the particular one of said second sets of display data corresponding to the information segment displayed in the region which is positionally coordinated with the actuated key.

25. In an industrial process control system for use with complex processes having a large number of conditions the values of which are to be measured and the measurements directed to associated means for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

said loops being organized in groups pertaining to respective process tasks; and

said groups being clustered as distinct areas of the overall plant;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said display device and arranged to be selectively transferred to said display memory to control the display;

a first set of said digital display data serving to present in separate display sectors of said display device summary information concerning respective process areas;

said summary information in each such sector comprising a listing of multi-character group identifiers each designating a corresponding one of said process groups forming the respective process area;

said digital storage memory having second sets of digital display data each representing detailed information concerning a corresponding process area summarized in a respective one of said sectors of the display produced by the digital data from said first set of said digital data;

display transfer means controlled by certain keys of said keyboard corresponding respectively to said display sectors;

each of said certain keys being operable, when said first set of digital display data is in said display memory, to transfer to said display memory the one of said second sets digital data providing the detailed information concerning the process area corresponding to the operated key; and

alarm indicator means for visually designating any one of said process areas represented by the display of said first set of digital display data and serving, whenever a process loop is in alarm condition, to designate the particular process area including such loop;

the operation of the one of said certain keys corresponding to such designated process area serving to present on said display device the detailed information covering the particular process area containing the process loop indicated as being in alarm.

26. Apparatus as claimed in claim 25, wherein said sets of display data each includes display data for presenting symbols on said display device in predetermined locations to identify the functions of preselected keys of said keyboard, including said certain keys, when the corresponding set of digital display data is presented on said device.

27. Apparatus as claimed in claim 25, wherein said group identifiers presented by said first set of display data are words describing a characteristic aspect of the respective group.

28. Apparatus as claimed in claim 25, wherein said second sets of display data serve to present a listing of the individual loops within the particular process area represented by each such second set of display data.

29. Apparatus as claimed in claim 25, wherein said alarm indication is developed by altering a characteristic of the portion of the display corresponding to the process area having a loop in alarm condition.

30. Apparatus as claimed in claim 29, wherein said alarm indication is developed by altering the intensity of a portion of the display presenting the group identifiers of the process area having a loop in alarm condition.

31. Apparatus as claimed in claim 29, wherein said alarm indication is developed by altering the representation of the group identifier of the group including the loop in alarm.

32. In an industrial process control system for use with highly complex processes having a large number of conditions the values of which are to be measured and the measurements used for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

said loops being organized in groups pertaining to respective process tasks; and

said groups being arranged as clusters representing respective preassigned areas of the overall plant;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said device and arranged to be selectively transferred to said display memory to control the display;

said sets of display data containing multiple levels of plant information comprising at least first, second and third levels;

a first set of said display data providing said first level of information and serving when transferred to said memory to present on said display device a number of separate information segments pertaining to respective preassigned areas of the plant under control;

alarm indicator means effective while said first set of display data is in said memory to visually designate any of said information segments to indicate that a process loop forming part of the corresponding process area is in an alarm condition;

said second level of information comprising a plurality of second sets of display data each representing a more detailed exposition of a corresponding one of the plant area information segments presented in said first level of information;

said third level of information comprising a plurality of third sets of display data each representing a still more detailed exposition of a respective process group identified in said second sets of display data;

means operable by the console operator when said first set of display data is in said memory for transferring to said memory any of said second sets of display data;

said second sets of display data presenting information in distinct regions of the display for the respective process groups of the particular process area, to provide for visual designation of any process group having a process loop in alarm condition; and

means operable by the console operator when any of said second sets of display data is in said memory for transferring to said memory any of said third sets of display data;

the process operator being enabled by said visual designation of the process area and process group having a loop in alarm condition, while said first and second sets of display data are presented, respectively to progress quickly and accurately from said first to said second information level, and from said second to said third information level, as he seeks to gain more detailed knowledge about the alarm condition.

33. Apparatus as claimed in claim 32, wherein an alarm is indicated on the display device by altering the appearance of a portion of the display related to the loop in alarm condition.

34. Apparatus as claimed in claim 32, wherein each of said information segments comprises a listing of words identifying the process groups included in the respective process area;

an alarm being indicated by altering the intensity of the identifying word of the process group having the control loop in alarm condition.

35. Apparatus as claimed in claim 34, wherein said second sets of display data present, for each process group of the corresponding process area, a listing of loop identifiers;

an alarm being indicated by altering the intensity of the identifier of the loop in alarm.

36. In an industrial process control system for use with complex processes having a large number of conditions the values of which are to be measured and the measurements directed to associated means for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

said loops being organized in groups pertaining to respective process tasks; and

said groups being clustered as distinct areas of the overall plant;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said display device and arranged to be selectively transferred to said display memory to control the display;

a first set of said digital display data serving to present in separate display sectors of said display device summary information concerning respective process areas;

said summary information in each such sector comprising a listing of multi-character group identifiers free of any display of loop information, each group identifier presenting symbols limited to the function of designating a corresponding one of said process groups forming the respective process area;

said digital storage memory having second sets of digital display data each representing detailed information pertaining to the loops in the process areas summarized in said sectors of the display produced by the digital data from said first set of said digital data;

display transfer means operable by the console operator when said first set of display data is in said display memory, for transferring to said display memory any of said second sets of display data; and

alarm indicator means for visually designating any one of said process areas represented by said first set of digital display data and serving, whenever a process loop is in alarm condition, to designate the particular process area including such loop, said alarm indicator means presenting an alarm indication positionally correlated with the display location of the process area containing a loop in alarm.

37. Apparatus as claimed in claim 36, wherein each of said second sets of display data is operable to identify on said display device all of the process loops of the process groups making up the corresponding process area;

whereby any process loop in alarm condition can be designated individually for the console operator.

38. An industrial process control system having a large number of process tasks distributed in respective areas of a process plant, with each of said process tasks comprising a number of interrelated process loops arranged in groups according to respective process operations, said system including a digital display system for allowing an operator to examine the alarm status of each area, group or loop while continuously maintaining alarm integrity on all process loops, comprising:

an operator'"'"'s console including a display device and a request-entry keyboard;

format generation means for presenting on said display device a hierarchical presentation of said process tasks by a succession of plant, area and group level displays each in response to a specific keyboard request, each of said level displays being segmented such that respective portions of said display device identify particular operational sections forming the process level being displayed;

said plant level display serving to present to said operator summary information on each of said process areas such that each segment of the display presents to said operator a listing of all groups forming a respective process area, each of said groups being further identified by a particular multi-character designator;

said area level display serving to present summary information of a selected one of said process areas in said segments of identification of the groups comprising said selected area with each of said display segments containing information pertaining to all loops forming a respective process group of said selected area;

said group level display serving to present summary information of a selected one of said area groups, said group level display identifying the loops comprising said selected group with each display segment containing detailed status information pertaining to a particular loop of the selected group;

means for compiling status information on each of said process loops independent of the particular display being presented;

segment selection keys each spatially positioned relative to a respective one of said display segments, each of said selection keys serving when actuated to present on said display a more detailed representation of the selected segment as defined by the next succeeding level in the display hierarchy;

means for comparing the status of each of said loops to a respective pre-established condition and upon sensing a loop at variance with its respective condition for presenting on said display device an alarm condition designator;

said alarm condition designator being presented in the display segment which corresponds to the loop in alarm regardless of the display level being presented and independent of changes in the position of said segment with changes in display level thereby allowing the operator to efficiently track an alarm indication from a higher order level display through more detailed display of the loop in alarm by visually correlating the segment of interest and its respective segment selection keys.

39. In an industrial process control system for use with complex plants of the type having a number of conditions the values of which are to be measured and the measurements used for developing corresponding process control signals for elements such as valves and the like to maintain the respective conditions at a desired set point, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display control for said display device adapted to receive digital data for controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said device and arranged to be selectively transferred to said display control to establish the display presented on said device;

a first plurality of said sets of digital data each containing data representing detailed information concerning the process loops and including data operable when transferred to said display control to develop graphic loop presentations wherein a relatively wide vertical bar shows by its height the value of the measurement for the corresponding loop, and wherein two vertical lines of identical height and contiguous respectively with the sides of said bar indicate by their height the set point of the corresponding loop, whereby when the measurement is below set point, the two vertical lines are readily distinguishable by the open space therebetween, and when the measurement is above set point, the vertical measurement bar is readily distinguishable by its appearance of thinness relative to a supporting thicker base at a level representing the set point value.

40. Apparatus as in claim 39, wherein each of said sets of digital loop data incorporates information respecting a plurality of distinct loops which are presented in respective sectors of said display.

41. Apparatus as in claim 39, wherein said graphic presentation comprises, adjacent said vertical bar, two small marks indicating high and low absolute alarm limits.

42. Apparatus as in claim 39, wherein said graphic presentation comprises, adjacent said vertical bar, a horizontal line indicating the value of an output signal from a controller.

43. Apparatus as in claim 42, wherein said graphic presentation comprises, adjacent said horizontal line two small marks serving as manual memory pointers, to provide the operator with an adjustable representation of a desired operating range.

49. In an industrial process control system for use with complex plants of the type having a number of conditions the values of which are to be measured and the measurements used for developing corresponding process control signals for elements such as valves and the like to maintain the respective conditions at a desired set point, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop, and wherein two loop values such as measurement and set point levels are to be displayed as an aid to an operator in controlling the process;

apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display control for said display device adapted to receive digital data for controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said device and arranged to be selectively transferred to said display control to establish the display presented on said device;

a first plurality of said sets of digital data each containing data representing detailed information concerning the process loops and including data operable when transferred to said display control to develop graphic loop presentations including a relatively wide bar showing by its length one of said loop values, and two thin bars of identical length contiguous respectively with the sides of said wide bar, indicating by their length the other of said loop values, whereby when one of said values is below the other, the two thin bars extend beyond the wide bar and are readily distinguishable by the open space therebetween, and when the reverse relationship exists between said loop values the wide bar is readily distinguishable by its appearance of being slightly thinner than a supporting thicker base consisting of the two thin bars together with the contiguous portion of the wide bar between said two thin bars.

50. In an industrial process control system for use with complex processes having a large number of conditions the values of which are to be measured and the measurements directed to associated means for developing corresponding process control signals for elements such as valves and the like, each combination of means for measuring a condition and for developing a corresponding control signal defining a process control loop;

said loops being organized in groups pertaining to respective process tasks; and

said groups being clustered as distinct areas of the overall plant;

display apparatus comprising;

an operator'"'"'s console including a display device and a data-entry keyboard;

a display memory for said display device containing digital data for continuously controlling the display;

a digital storage memory comprising a plurality of storage sections each with a set of digital display data defining a corresponding complete display for said display device and arranged to be selectively transferred to said display memory to control the display;

a first set of said digital display data serving to present in separate display sectors of said display device summary information concerning respective process areas;

said summary information in each such sector comprising a listing of multi-character group identifiers each designating a corresponding one of said process groups forming the respective process area;

said digital storage memory having second sets of digital display data each representing detailed information pertaining to the loops in the process areas summarized in said sectors of the display produced by the digital data from said first set of said digital data;

display transfer means operable by the console operator when said first set of display data is in said display memory, for transferring to said display memory any of said second sets of display data; and

alarm indicator means for visually designating any one of said process areas represented by said first set of digital display data and serving, whenever a process loop is in alarm condition, to designate the particular process area including such loop;

said alarm indicator means comprising means to alter the visible character of the listing of group identifiers representing the process area containing the loop in alarm.

51. Apparatus as claimed in claim 50, wherein said alarm indicator means comprises means to alter the visible character of the particular group identifier representing the process group containing the loop in alarm.

52. Apparatus as claimed in claim 51, wherein said indicator means causes said particular group identifier to appear to blink intermittently.