GB1145981A - Improvements in or relating to a method and apparatus for the visual presentation ofinformation relating to a parameter value at each of a plurality of test points - Google Patents

Abstract

1,145,981. Cathode - ray tube displays. UNITED POWER CO. Ltd. 17 March, 1966 [17 Dec., 1964], No. 51392/64. Heading H4T. The condition of each of a plurality of test points in a threedimensional layout is sequentially sampled, converted into a representative electrical signal and displayed on a cathode-ray tube in a configuration representative of the lay-out. The embodiments described are concerned with displaying indications of temperature inside the core of a nuclear reactor in which temperature sensing devices, e.g. thermocouples, are disposed throughout the core in a series of vertically-spaced, horizontal planes the sensing devices of any one plane lying in a series of concentric bands. To simulate such lay-out the display tube is scanned in a series of concentric ellipses for each horizontal plane P 1 , P 2 , P 3 , Fig. 1, the beam being brightened at positions corresponding to the location of the thermocouples 5-8 and at such positions departure from normal of the sensed temperature conditions are indicated by + or - symbols generated by the addition of further signals to the vertical and horizontal deflection circuits for the + symbol or to the horizontal circuit alone for the - symbol. Alternatively, the sense of the departure from the normal may be indicated by producing a change in the colour of the display. Also, a three-dimensional appearance may be realized by employing intensity modulation in which a reduction in brightness is utilized to give an impression of increased distance from the observer. For production of the ellipsoidal patterns of brightened spots the output of a master generator 9, Fig. 2, operating at a frequency n x p x q x f c.p.s. (where n = number of thermocouple positions per ellipse, p = number of vertical planes, q = number of ellipses in each plane and f = repetition frequency of the whole display) controls a Schmitt trigger 10 supplying spot brightening pulses to the beam intensity control amplifier 22 and after division by n in divider 11 and filter-amplification in 12 is fed to the vertical deflection amplifier 19 via an adjustable step attenuator 17 and to the horizontal deflection amplifier 18 via a 90-degrees phase shifter 15 and an adjustable step attenuator 16, both attentuators being step controlled by a staircase waveform from generator 13 which divides the output of divider 11 by the factor q to produce the concentric ellipsoidal traces and the vertical deflection being further controlled by supplying amplifier 19 with a staircase waveform from divider-generator 14- dividing the output of generator 13 by the factor pto produce the required number of vertical planes. The sampling operation is effected by a device 25, Fig. 3, which is driven by a unit 24 controlled by the pulse output of the trigger 10 and supplies a voltage to amplifier 26 representative of the sign and magnitude of the departure from normal of the output from each of the sampled thermocouples. The thermocouples may be sampled in a point-bypoint co-ordinate manner or they may be sampled in a pre-arranged order of importance. The output of (26) is supplied via a diode (28b) and via an inverting amplifier (27) and diode (28a) to a gate (35) and to a modulator (30) to amplitude modulate the output of a generator (29)-having a frequency high compared to that of generator (9)-the modulated signal, the amplitude of which is indicative of the magnitude but not the sign of the departure from normality, being fed to further gates (31), (32). On the occurrence of a pulse from trigger (10) a monostable trigger (33) changes state and opens gate (31) which passes the modulated signal to an auxiliary input (A) of the horizontal deflection amplifier (18) to superimpose a " minus " ( - ) sign on the trace which, if the departure from normality is in the positive direction, is transformed into a " plus " (+) sign by the opening of gate (32)-when (33) reverts to its stable state, within the period of the pulses from trigger (10)-which passes the same modulated signal to an auxiliary input (A<SP>1</SP>) of the vertical deflection amplifier (19). If the departure is not in the positive direction the output of amplifier (27) is arranged to prevent the opening of gate (32). During the production of the symbols, continued brightening of the tube beam is effected by passing the output of diodes (28a, 28b) to an auxiliary input (B) of the intensity control amplifier (22) by means of gate (35) opened by the output of a delay circuit (34) fed with a signal from device (25) to allow conditions to become stable after each sampling operation. Since the amplitude of the modulated signal from (30) is directly related to the magnitude of the departure from normality the size of the " plus " and " minus " symbols is also so related. In an alternative arrangement a three-gun colour tube (Fig. 4) utilizing the deflection circuitry of (Fig. 2) is employed for the display, the output of amplifier (26)- conveying the " departure " signal from the device (25)-being fed to a further amplifier (37) of unity gain and the outputs of both amplifiers being fed via respective oppositely poled diodes (39), (38) to the cathodes of the green and blue gun via respective gates (41), (40). These cathodes are connected to the control electrodes of the red and green guns respectively so that when gates (40), (41) are opened by monostable trigger (33) a " plus " departure signal is fed via diode (39) and gate (41) to the control electrode of the red gun thus producing a " red " display and simultaneously, by virtue of the cathode connection, decreasing the green gun beam current, whilst if the " departure " signal is " negative ", the latter is fed via diode (38) and gate (40) to cause an increase in the blue gun beam current and a decrease in that of the green gun. Thus, temperature above normal is indicated by a " red " display and temperature below normal by a " blue " display whilst if there is no departure from normal a " green " display is produced. During the absence of a signal input at (c)-from the trigger (10, Fig. 1)-the D.C. levels of the cathodes and control electrodes determined by the potentiometer chain result in an overall low intensity white illumination of the tube screen.