| 摘要 |
897,912. Automatic control systems. ROBERTSHAW - FULTON CONTROLS CO. Sept. 29, 1958 [Nov. 25, 1957], No. 31070/58. Drawings to Specification. Class 38 (4). Electrical error signals produced by deviations of a plurality of variables, such as pressure, thermocouple-detected temperature, position of a body &c., are applied through series impedances to the contacts of a rotary selector switch which successively applies them to a D.C. or chopper-fed A.C. amplifier. The amplifier output is applied through a further, synchronously-operated, selector switch to successively operate appropriate automatic correctors for the variables. At each control position of the selector switches an impedance connected between the contacts of the switches forms a feed-back path in shunt with the amplifier. At one position during each revolution of the selector switches the output of the amplifier may be fed back to its input to eliminate drift. Various arrangements of the series and shunt impedances to introduce integral and differential components of control are described. The period of rotation of the selector switches is made an odd multiple of half the period of the mains supply to reduce mains interference signal pick-up. |
