JPS57111617A - Temperature controller - Google Patents

Abstract

PURPOSE:To raise temp. smoothly by raising the article temp. up to a target value while controlling the differential temp. between room temp. and the article temp. within a certain temp. range, then controlling the temp. of a material to be heated on the basis of the target value of the heating time necessary for said material. CONSTITUTION:Temp. sensors 1, 2 detect room temp. and article temp. respectively, and detects at 5 a differntial temp. DELTAt via amplifier circuits 3, 4. In an initial state, the differential temp. DELTAt is small and therefore the output of a differential temp. lower limit comparator 11 goes to the H level, and is transmitted to an AND circuit AND1 of a relay controlling circuit 17. The other input of the circuit AND1 receives the output signal of the H level from the comparator 15, and excites a relay 18, which in turn starts a heater 19. When the room temp. rises, the differential temp. DELTAt and the set 6 differential upper limit value DELTAtmax are compared 10 of the upper limit of the differential temp., by which an FF1 is reset to stop the heater 19. On the other hand, the output of the circuit 4 is transmitted to an A/D conversion circuit 12, the room temp. converted of the time up to the attainment of the certain level whereby is compared of the magnitude of the target value ts of a temp. setter 14 by a magnitude comparator MC1 of the circuit 15.