Patent GB-1383661-A (GB)
Title: Temperature measuring equipment
IPC: G06F7/66
Filed: 1972-04-25
Abstract: 1383661 Calculating N SHIMOMURA 25 April 1972 [30 April 1971 21 July 1971 4 Oct 1971 16 Dec 1971] 19218/72 Heading G4A To provide an indication of temperature as measured by a sensor whose output is a polynomial function of temperature, a computing circuit makes, in dependence upon the temperature sensor signal, repetitive cascade accumulations of the constants of the polynomial to provide solutions thereto and accordingly provide an indication of the temperature. The number of repetitive cascade accumulations necessary to bring the accumulated count into agreement with the temperature sensor signal indicates the temperature.  Fig. 1 shows an accumulating circuit for third order polynomials. Memories 13 and 16 contain the constants of the second and third powers. Control pulses at terminal 1, with switch 43 on contact 44, cause the contents of memory 13 to be added to register 14 and via delay 13 the contents of register 14 to be added into counter 2. Similarly cascade accumulation takes place with memory 15 and registers 16 and 17 adding to counter 2. The control input pulses at 1 are added directly into the counter 2 to give the first order of the polynomial. Thereby the number of control pulses to be added at 1 to bring the contents of counter 2 to represent the current temperature sensor output signal indicates the temperature sensed. The polynomial expressing temperature as a function of the control signal is also achieved by circuit 39 but with the switch 43 set to contact 45. For each input pulse at 1, the content of the 2‹ bit position via a line 25 is read alternately into memory 21 in true form and memory 23 in inverted form. The two memories controlling via a comparator 24 a gate 28, which is thereby opened to pulses from input 1 only if there has been no change in the 0 bit position of the counter 2 from its current state and that corresponding to the previous input pulse, closed if there has been a change. Further by causing negative constants in the memories 13 and 15 to be added in counter 2 additively and positive constants negatively, the result in the counter 2 after a number of input pulses at 1 representative of the temperature sensor signal represents the temperature measured. Fig. 29 shows an alternative arrangement of accumulators for a fifth order polynomial in which for each input pulse at terminal 121 the contents of all memories 124, 125, 126 and 127 are read into registers 122, 130, 129, 128 and by means of delay lines 132, 133 and 134 the contents of the register are cascade accumulated into register 122. In combination with any of the above temperature-measuring arrangements a further cascade accumulator may be arranged to receive the number of control pulses received by the temperature measuring arrangement to give an output simulating the output signal of a temperature sensor at that temperature. The temperature-measuring arrangements may receive temperature sensor signals from different sensors in turn, in which ease the contents of the memories are changed accordingly. When using a thermocouple the output temperature indication may be made relative to a scale zero and not to the reference temperature of the thermocouple.