| 摘要 |
PURPOSE:To obtain a controller with high safety by inserting a switching element in series with a correction resistor connected in parallel with a thermister to improve the nonlinear resistance value change and detecting disconnection of a thermister. CONSTITUTION:A controller 1 comprising a microcomputer has an I0 input terminal 3 and an OH output terminal 7 or the like, a positive characteristic thermister 11 of a bridge circuit 15 detects the temperature of an object to be heated to control power application to a heater 9 and the disconnection fault of the said thermister 11 is displayed on a display device 10 from an OC output terminal 6. In this case, a transistor (TR) 20 being the switching element and a correcting resistor 19 are provided in parallel with the thermister 11, a power supply 8 is applied to an IV input terminal 4 via a switch 26, an H signal from the O0 output terminal 5 inactivates the said TR20 and a disconnected wire detection signal of the thermister 11 is obtained from a connecting point A. When the thermister 11 is normal, an L signal is outputted from the O0 output terminal 5 and the correction resistor 19 corrects the nonlinearity of the thermister 11. |
