Patent GB-832695-A (GB)
Title: Improvements in and relating to high speed gauging apparatus
IPC: G01R1/30
Filed: 1956-10-10
Abstract: 832,695. Potentiometric voltage measurements. SHEFFIELD CORPORATION. Oct. 10, 1956 [Oct. 10, 1955], No. 30864/56. Class 37. In an arrangement for determining in what voltage range an input voltage V lies, the receipt of the input voltage causes a voltage selector to apply stepby-step increasing voltages in succession to a comparator, to which a voltage which is a function of V is also applied, until such time as the voltage applied by the selector becomes equal to or greater than the function of V, whereupon the selector is stopped in the position characteristic of the voltage range required. An input voltage V is applied to terminals 24, 25 and at the same time switch 28 is closed, either automatically or manually and the resulting current pulse via condenser 31 energizes relay 27 for approximately 30 milliseconds. The memory condenser 38 is thus charged to the input voltage V, and the battery 29 energizes the transfer switch 90 cocking it for movement of its arms to their upper positions. The voltage on condenser 38 is amplified by 37 and applied to the input of D.C. amplifiers 43 and 65 in cascade the output of the latter operating the high speed relay 68. At the end of the pulse, relay 27 restores, and transfer switch 90 thereupon moves its arms to their upper positions. Battery 29 thus energizes actuator 97 of the upper selector switch 113 which proceeds to step the wipers of that switch over their banks under control of interrupter contacts 105. A negative voltage which increases at each step is thus fed from the potentiometer tops 210-219 via the bank 112 to the input 42 of D.C. amplifier 43 until, at, say, the ninth step 138, this voltage becomes equal to or greater than the voltage derived from the input voltage V. The output of amplifier 65 then drops to zero and relay 68 releases, whereupon battery 29 energizes relay 77, which operates with delay to disconnect actuator 97, which, being already cocked, moves the wipers to their next position. Lockin relay 80 is operated and relay 77 is held. When the next input voltage is applied, the operation of relay 27 releases relays 80 and 77, connects battery 29 over the right-hand bank of selector switch 113 to operate the ninth output relay 239, and also re-energizes transfer switch 90 which cocks. The output from amplifier 65 re-operates relay 68. At the end of the input pulse the transfer switch 90 moves its arms to their lower positions, the output relay 239 is held over contact 289, and the corresponding output device 259 is operated in a local circuit to indicate the voltage range in which the first input voltage lies. The lock-in relay 80 is re-operated but 77 remains unoperated. Actuator 97 is again energized over off-normal contact 96 and the upper selector switch 113 is homed. At the same time the actuator 99 of the lower selector switch 117 is energized and that switch commences stepping to determine in like manner the range in which the second input voltage lies. When the range is reached relay 77 comes up as before to stop the switch drive. When relay 27 next operates it releases the ninth output relay 239 (first input voltage) and operates that corresponding to the second input voltage. In the arrangement described, the input voltages are representative of a characteristic such as the size, dimension, weight, pressure or electrical resistance of a product, the products being classified in accordance with the voltage range in which the voltage falls.