US3816791A

US3816791A - Incremental vertical sweep system for display of information in selected horizontal bands on a crt

Info

Publication number: US3816791A
Application number: US00316919A
Authority: US
Inventors: D Fluegel
Original assignee: Phillips Petroleum Co
Current assignee: Applied Automation Inc; Phillips Petroleum Co
Priority date: 1972-12-20
Filing date: 1972-12-20
Publication date: 1974-06-11
Anticipated expiration: 1991-06-11

Abstract

Information, such as process variables, can be displayed in selected vertically spaced horizontal bands on a cathode ray tube by employing means for modifying the waveform of the vertical sweep voltage to the CRT. In one embodiment a generally stairstepped waveform voltage is produced, with each vertical segment corresponding to the vertical spacing between adjacent horizontal bands. This stairstepped voltage is added to the generally sawtooth waveform of the conventional vertical sweep voltage. Spike pulses, corresponding to the completion of a horizontal band, can also be added to improve the movement of the electron beam to the next horizontal band. A slide projector can be employed to provide a graphic display of the process on the CRT, corrdinated with the positions of the information displays.

Description

United States Patent [1 1 Fluegel June 11, 1974 INCREMENTAL VERTICAL SWEEP SYSTEM FOR DISPLAY OF INFORMATION IN SELECTED HORIZONTAL BANDS ON A CRT [75] Inventor: Dale A. Fluegel, Bartlesville, Okla.

[73] Assignee: Phillips Petroleum Company,

Bartlesville, Okla.

[22] Filed: Dec. 20, 1972 [211 App]. N0.: 316,919

Primary Examiner-Maynard R. Wilbur Assistant Examiner-J. M. Potenza [5 7] ABSTRACT Information, such as process variables, can be displayed in selected vertically spaced horizontal bands on a cathode ray tube by employing means for modifying the waveform of the vertical sweep voltage to the CRT. In one embodiment a generally stairstepped waveform voltage is produced, with each vertical segment corresponding to the vertical spacing between adjacent horizontal bands. This stairstepped voltage is added to the generally sawtooth waveform of the conventional vertical sweep voltage. Spike pulses, corresponding to the completion of a horizontal band, can also be added to improve the movement of the electron beam to the next horizontal band. A slide projector can be employed to provide a graphic display of the process on the CRT, corrdinated with the positions of the information displays.

8 Claims, 3 Drawing Figures [52] U.S. Cl. 315/18, 340/324 AD [51] Int. Cl. HOlj 29/70 [58] Field of Search 3l5/l8, 19, 22; 340/324 A, 340/324 AD [56] References Cited UNITED STATES PATENTS 3,054,998 9/l962 Cooper et al. .i 343/5 3,388,39l 6/l968 Clark 315/22 3,449,620 6/1969 Caron et al. 315/22 3,631,458 l2/l97l Caron 315/18 r l4 COMPUTER 1223;

HORlZONTAL SWEEP- rVERTlCAL SYNC VERTICAL I? Q l& 22 2 g g COUNTER COUNTER 40 CIRCUIT 5 TO BY 24 To+ BY l0 HORIZONTAL SYNC l r32 47 ONE SHOT 34 35 42 -W%\: 43 r w'lm {27 i2 VEiJLCAL ONE SHOT MV SLIDE PROJECTOR mmmmn m4 3.816391 SHEEI 3 0f 3 1 {CATHODE RAY TUBE FIG. 3

INCREMENTAL VERTICAL SWEEP SYSTEM FOR DISPLAY OF INFORMATION IN SELECTED HORIZONTAL BANDS ON A CRT This invention relates to information display systems. In one aspect the invention relates to a process and apparatus for displaying information on a cathode ray tube. In a specific aspect the invention relates to an electronic system for modifying the vertical sweep pattern for a cathode ray tube.

It has become customary to provide visual displays of frequently updated information, for example, the presentation of process operating conditions on a process operator's console. One technique employs a cathode ray tube which is adapted for use with an optical projector to provide an overlay of a process diagram correlated with the presentation of the electronically displayed information. However, the program capacity of the computer required to determine the proper location for each bit of electronically displayed information is quite large and expensive. It has become desirable to achieve the presentation of information on selected areas of a cathode ray tube display with a minimum utilization of computer capacity.

Accordingly, it is an object of the invention to provide a new and improved system for the visual presentation of information. It is an object of this invention to provide a new method and apparatus for presenting information on a cathode ray tube display. Another object of the invention is to reduce the computer capacity required to present information on selected areas of a cathode ray tube display. Yet another object of the invention is to reduce the cost of a visual display system combining optical and electronic presentation of information. Other objects, aspects and advantages of the invention will be apparent from a study of the specification, the drawings and the appended claims to the invention.

In accordance with the present invention, it has been discovered thac these objectives can be achieved by modifying the waveform of the vertical sweep voltage to the CRT. In one embodiment for displaying information in a plurality of vertically spaced horizontal bands on a CRT, a generally stairstepped waveform voltage is produced and combined with the conventional generally sawtooth waveform vertical sweep voltage, each vertical segment of the stairstepped waveform voltage corresponding to the spacing between adjacent horizontal bands. Spike pulses, corresponding to the completion of each horizontal band, can also be combined with the vertical sweep voltage to improve the movement of the electron beam from the end of one horizontal band to the start of the next horizontal band.

In the drawings FIG. 1 is a schematic diagram of a CRT display system embodying the present invention;

FIG. 2 is a graphical presentation of the voltage paterns at several locations in the system of FIG. 1; and

FIG. 3 is a representation of a typical CRT display producible by the system of FIG. 1.

Referring now to FIG. I, a cathode ray tube 11 is provided with a conventional horizontal sweep circuit 12 and a conventional vertical sweep circuit 13. The dot patterns for letters of the alphabet, numbers, and/or other symbols are stored in serial memory 14. Computer 15 addresses the desired letter, number of symbol in memory 14, which then provides a series of pulses over several horizontal sweep periods to the video signal input of CRT 11. The output of clock and counter ciruuit 16 can be applied to horizontal sweep circuit 12, vertical sweep circuit 13, and memory 14 to provide synchronism of the variouus signals. In the embodiment shown in FIG. 3, there are 10 vertically spaced information presentation bands 17, each band comprising 24 horizontal sweep lines. Each band 17 can be employed to present two horizontal rows of characters where, for example, each character is represented in serial memory 14 as being within the third through the tenth horizontal sweeps of a set of 12 horizontal sweeps, thereby providing a. spacing of four horizontal sweeps between the upper and lower row of characters in a given band. The horizontal sweep output signals from horizontal sweep circuit 12 are applied to CRT 11, and the horizontal synchronism signals are applied to the input of digital counter 18. Unless blocked by a reset signal, counter 18 produces an output pulse 21 for each 24 input pulses. The output pulses 21 of counter 18 are applied to the input of digital counter 22. The digital bits registered by counter 22 are applied in parallel to the inputs of digital-to-analog converter 24. The analog output voltage waveform 25 produced by DAC 24 is in the form of a stairstep with each riser being the result of the occurrence of an input pulse 21 to counter 22. Vertical sweep circuit 13 produces a vertical sync pulse corresponding to the completion of each vertical scan cycle, i.e., the completion of all 10 horizontal bands 17. The vertical sync pulse triggers one-shot multivibrator 27 to produce an output pulse 28 from the vertical sync pulse. The output pulse 28 is amplified by amplifier 29 and then applied to the reset inputs of

digital counters

18 and 22 to reset the counters to zero and to block the registration of any input pulses to either counter during the duration of pulse 28. The duration of pulse 28 is selected to permit sufficient time for the CRT beam to move from the lowermost horizontal sweep in the bottom band 17 to the initial horizontal sweep of the top band 17.

The output pulses 21 from digital counter 18 are also applied to the input of oneshot multivibrator 32. The output pulses 33 from multivibrator 32 are applied through variable resistor 34 and resistor 35 to the summing junction 36 which is connected to one input of sweep mixer amplifier 37. The vertical sweep output of vertical sweep circuit 13 has a generally sawtooth waveform 38 and is applied through resistor 39 to summing junction 36. The stairstep waveform output of DAC is applied through variable resistor 40 and resistor 41 to summing uunction 36. The output of amplifier 37 is applied through feedback resistor 42 to summing junction 36. The output of amplifier 37 is also applied through resistor 43 to the input of amplifier 44. A feedback resistor 45 is connected between the input and output of amplifier 44, while a variable resistor 46 and a resistor 47 connects to the input. of amplifier 44 to a reference voltage. The output of amplifier 44 has the waveform 48 which is representative of the algebraic summation of the generally sawtooth waveform 38, the generally stairstep waveform 25 and the step pulses 33. The output of amplifier 44 is connected to the input terminal of vertical amplifier 49. The output of amplifier 49 is connected to the vertical input of CRT 11. The vertical segments of waveform 25 cause the electron beam to move from the bottom horizontal line of one band 17 to the top horizontal line of the next lower band 17 at a significantly more rapid pace than would have been achieved by the vertical sawtooth waveform 38 alone. This will usually be accomplished in one or two horizontal sweeps. The step pulses 33 are employed in the presently preferred embodiment of the invention to move the electron beam from one band 17 to another band 17 at an even more rapid rate than would be achieved by a combination of

waveforms

25 and 38. This permits a greater uniformity of the spacing of the leading horizontal lines in a band 17.

An optical projector 51, for example, a conventional slide projector, can be positioned adjacent the optical window 52 in the CRT 11. This permits the optical projection of a process layout diagram onto the rear surface of the viewing screen of CRT l 1. A simplified process layout diagram 53 of fractionator is shown in FIG. 3. The solid line layout 35 is produced on the screen of CRT 11 by projector 51, while the information on process operating conditions shown within the boxes are electrically produced by computer 15 and the system of FIG. 1. In the illustrated diagram the feed to the fractionator is 400 barrels per hour and comprises 200 barrels per hour of component A, 80 barrels per hour of component B, and 120 barrels per hour of component C. The overhead stream is withdrawn from the fractionator at a rate of 1,000 barrels per hour and is heat exchanged with a water stream having an inlet temperature of 80F. The external reflux is passed to the fractionator at a rate of 800 barrels per hour, while a liquid overhead product containing 97.5 volume percent component A is withdrawn at a rate of 200 barrels per hour. A sidedraw stream comprising 87.5 volume percent of component B is withdrawn at a rate of 80 barrels per hour, while a bottoms product stream comprising 95 volume percent component C is withdrawn at a rate of 120 barrels per hour. Steam having a temperature of 250F is passed to the reboiler of the fractionator.

Although the invention has been described in terms of the illustrated embodiment utilizing 1O horizontal bands of 24 lines each, it is obvious that another number of horizontal bands having a different line count could be employed. While the bands 17 have been shown as being evenly spaced, it is within the contemplation of the invention to alter DAC 24 to provide differing lengths for the verticalsegments of the stairstepped waveform 25. Where it is desired that bands 17 be provided with differing numbers of vertical lines, a corresponding number of counters 18 can be employed, with the output of each counter being sequentially applied to the input of counter 22 and multivibrator 32. Thus a first counter 18 could count 24 lines for the first band 17, while a second counter could count 12 lines for the second band 17, and so on. If desired, computer 15 can be programmed to operate slide projector 51 to project the desired layout on the screen of CRT 11. Computer 15 can also be programmed to utilize a light pen or a cursor, as known in the art.

Other reasonable variations and modifications are possible within the scope of the foregoing disclosure, the drawings and the appended claims to the invention.

I claim:

1. Apparatus for displaying information on at least two vertically spaced selected areas of the display screen of a cathode ray tube which is provided with means for generating a generally sawtooth vertical sweep voltage, comprising means for establishing for each of said vertically spaced selected areas a signal responsive to the occurrence of the desired plurality of horizontal sweeps for the respective one of said vertically spaced selected areas, means responsive to the establishing of said signal for one of said vertically spaced selected areas for modifying said generally sawtooth vertical sweep voltage to temporarily increase the vertical sweep rate to at least substantially immediately move the cathode ray tube beam to the initial horizontal sweep of the next subsequent one of said vertically spaced selected areas.

2. Apparatus in accordance with claim 1 wherein the means for establishing a signal responsive to the occurrence of the desired plurality of horizontal sweeps comprises a first digital counting means, and wherein the means for modifying the vertical sweep voltage comprises a second digital counter which is triggered each time the output of said first digital counting means indicates the desired plurality of horizontal sweeps for the respective one of said vertically spaced selected areas has been made, means for converting the output of said second digital counting means to an analog voltage which has a generally stairstepped configuration wherein each step corresponds to a respective one of said vertically spaced selected areas, and means for adding said generally sawtooth vertical sweep voltage and the generally stairstepped voltage.

3. Apparatus in accordance with claim 2 further comprising a one-shot multivibrator, which is triggered each time the output of said first digital counting means indicates the desired plurality of horizontal sweeps for the respective one of said vertically spaced selected areas has been reached, to produce an output pulse each time the desired plurality of horizontal sweeps is completed; and wherein said means for adding comprises means for adding the output pulses from said multivibrator, said generally sawtooth vertical sweep voltage, and said generally stairstepped voltage.

4. Apparatus in accordance with claim 3 further comprising means for generating a vertical synchronization signal, a second multivibrator which is triggered to produce an output pulse corresponding to each vertical synchronization signal, and means responsive to the output pulse from said second multivibrator to reset and block said first and second digital counting means during the duration of the output pulse of said second multivibrator.

5. Apparatus in accordance with claim 2 further comprising means for generating a vertical synchronization signal, a one-shot multivibrator which is triggered to produce an output pulse corresponding to each vertical synchronization signal, and means responsive to the output pulse from said multivibrator to reset and block said first and second digital counting means during the duration of the output pulse of said multivibrator.

6. Apparatus in accordance with claim 1 further comprising a cathode ray tube having a video input, a horizontal sweep input, and a vertical sweep input, means for applying the thus modified vertical sweep voltage to said vertical sweep input, means for generating a horizontal sweep voltage and for applying the thus generated horizontal sweep voltage to said horizontal sweep input.

7. Apparatus in accordance with claim 6 further comprising a digital computer, a memory containing 6 visual image on the screen of said cathode ray tube, and wherein said computing means is provided with programming means to associate the time of occurrence of the transmission of each of said symbol patterns to said video input with a specific portion of said visual image. =l

Claims

7. Apparatus in accordance with claim 6 further comprising a digital computer, a memory containing symbol patterns, and means responsive to an output of said computer to transmit one of said symbol patterns from said memory to said video input.

8. Apparatus in accordance with claim 7 wherein said cathode ray tube is provided with a rear window, and further comprising an optical projection means associated with said rear window for optically projecting a visual image on the screen of said cathode ray tube, and wherein said computing means is provided with programming means to associate the time of occurrence of the transmission of each of said symbol patterns to said video input with a specific portion of said visual image.