Temperature signal auto-diagnosis circuit and diagnosis method thereof

The invention provides a temperature signal auto-diagnosis circuit and a diagnosis method thereof and relates to the technical field of industrial control. The technical problem of temperature signal reliability improvement is solved. The temperature signal auto-diagnosis circuit comprises a temperature output loop, an analog-digital conversion module and a reference signal module. A micro-current output unit for outputting micro-current to the analog signal input end of the analog-digital conversion module is built in the analog-digital conversion module. The output end of the temperature output loop is connected to the analog signal input end of the analog-digital conversion module through an output capacitor, and the reference signal output end of the reference signal module is connected to the reference signal input end of the analog-digital conversion module. Micro-current is output to the analog signal input end of the analog-digital conversion module through the built-in micro-current output unit, the analog-digital conversion module monitors an input signal of the analog signal input end, and disconnection of temperature signals output by the temperature output loop is determined when a voltage value of the input signal exceeds a temperature range. By the adoption of the temperature signal auto-diagnosis circuit and the diagnosis method, temperature signal reliability can be improved.