Patent GB-1510864-A (GB)
Title: Data transfer and control system for liquid dispensers
IPC: G01D4/00
Filed: 1975-05-21
Abstract: 1510864 Remote data indicating system; alpha numeric displays and circuits therefor GENERAL ATOMIC CO 21 May 1975 [20 June 1974] 21818/75 Headings G4H and G5C In a system for providing remote indication of data relating to the dispensing of fluid from one or more dispensers, and for controlling the dispensers, a central control 42, Fig. 4 sequentially interrogates individual control means 40, Fig. 5 associated with respective dispensers to gather the said data which is transmitted to individual console control means 44 (one for each dispenser) via the central control 42 for display 48, the central control comprising means 132, 138 for generating address signals which are transmitted both to the dispenser and to the console control means. As described, the dispensers are petrol pumps and the central and console control means are located together under the control of an attendant (Figs. 1, 3, not shown). Signals are transmitted serially, using pulse code modulation with a single carrier frequency, over the existing power lines. Operation of a reset lever by a customer at a pump causes a service request signal to be received by control 42. A reset motor enable signal 110 is sent to the dispenser control 40 (relay 90) which returns a reset complete signal to zeroize display 48 in the corresponding console control 44. A signal 108 is then sent to enable operation of the pump motor (relay 96) and fluid is dispensed, transducers 146, 153 generating "1 cent" and "0À1 gallon" pulses for display 48 which normally displays the accumulated cost, but which displays the quantity dispensed upon actuation of a switch 52. When the hose is replaced at the end of the dispensing operation a signal is sent to control 44 to cause the display to flash. Upon completion of the sale, the attendant presses a 'paid' button 52 to reset the display. A 'run/ stop' button 54 on the console allows the attendant to suspend operations if, e.g. a smoker or a drunkard tries to operate a pump. The dispenser addresses ID1-ID4 (for up to 8 pumps) are generated sequentially by a counter 138 and are fed with signals 108, 110 and a parity bit to a register 124 from which they are transmitted via a modulator 128 in their time slot. Reception at 42 of correct data from 40 causes counter 138 to be incremented; if incorrect or no data is received during a particular time slot, counter 138 is automatically incremented by means 136 after a preset time. When data is received by means 40 and 42-44 it is checked for parity and accepted if the generated address ID1-ID4 corresponds with a prestored unique reference 98, 104. Data at means 40 is received by and transmitted from shift registers 82, 124. Each transducer comprises an LED-phototransistor combination 153, the light path between which is interrupted by the rotation of a toothed disc 146 driven by the fluid dispenser (Fig. 2, not shown). The cost and quantity pulses are stored in registers 99, 100, Fig. 16 having sequentially actuated decimal and binary outputs 10<SP>0</SP>-10<SP>3</SP> and 1-8 which are fed via gating circuits controlled by switch 50 to display driver 290 and seven-bar decoder 292 for a four digit display, e.g. LED; decoder 292 is controlled by a "blink" oscillator 294 and the display may indicate decimal points in respective positions for both quantity and price. Descriptions are provided with reference to Figs. 6-15, not shown) of the various circuit "boxes" shown on Figs. 4 and 5.