0, S1, S2, . . . . SN, and the outputs may be transmitted to components 301, 302, and 303 which detect radio wave signals and abnormalities.

The number N of combined outputs may pass the radio wave signal selector 303 and be transmitted to the radio wave signal comparator 302. The radio wave signal comparator 302 may sequentially compare the signal phase and the signal strength of N−1 target radio wave signals except for the reference target radio wave signal So and the reference target radio wave signal and transmit the difference value to the device logic circuit 301. The device logic circuit 301 may be a computer or a control device. The device logic circuit 301 may calculate relative ratio information about the signal phase and the signal strength of different target radio wave signals based on the difference value. The device logic circuit 301 may determine whether the calculated ratio information matches the reference ratio information. Here, the reference ratio information may be a predetermined relative ratio information of the signal phase and signal strength allocated to different target radio wave signals. The device logic circuit 301 may determine that the operation of the heat treatment device is normal if the reference ratio information and the calculated ratio information match and determine that the operation of the heat treatment device is abnormal if the reference ratio information and the calculated ratio information do not match. If the reference ratio information and the calculated ratio information do not match, the channel transceiver 306 may correct the signal phase and the signal strength. Or, if the reference ratio information and the calculated ratio information do not match, the device logic circuit 301 may perform a logic calculation operation which controls the entire device to run an alarm and an operation stopper.

The components 301, 302, and 303 which detect the radio wave signal and abnormalities in FIG. 3 will be illustrated in more detail in FIG. 4. The number N of combined outputs S0, S1, S2, . . . . SN are input to the component of FIG. 4, and the reference target radio wave signal So may pass an attenuator 401 and be divided into two sub-signals of the reference target radio wave signal through a divider 410. One of the sub-signals of the two reference target radio wave signals may be transmitted to a difference value detector 409 between the half-wave phase signal and the signal strength, and the other one may pass a 90 degree phase signal shifter 411 and be transmitted to a difference value detector 408 between the half-wave phase signal and the signal strength. The rest of the N−1 target radio wave signals except the reference target radio wave signal may pass the attenuators 402 and 403. Then, the rest of the N−1 target radio wave signals except the reference target radio wave signal may pass switches 404, 405, and 406 so the signals are selected sequentially. The target radio wave signals selected sequentially may be divided into sub-signals of two target radio wave signals through a divider 407. The sub-signals of the two target radio wave signals may each be transmitted to a difference value detector 408 and 409 between the half-wave phase signal and the signal strength. In one difference value detector 408 between the half-wave phase signal and the signal strength, the phase signal and signal strength of the rest of the N−1 target radio wave signals, except the reference target radio wave signal So which is 90 degrees phase signal delayed and the reference target radio wave signal, may be sequentially compared, and the difference value between the half-wave phase signal and the signal strength may be detected to be output by a difference value calculator 412 of the one wave signal and signal strength.

In the difference value detector 409 between the half-wave phase signal and signal strength, the rest of the N−1 target radio wave signals except the reference target radio wave signal So and the reference target radio wave signal may be compared in terms of phase signal and signal strength, and the difference value between the half-wave phase signal and the signal strength may be calculated. The difference value may be output from a difference value calculator 412 between the one wave phase signal and the signal strength, and the difference value calculator 412 between the phase signal and the signal strength may calculate the difference value between the phase signal and the signal strength with respect to the one wave reference target radio wave signal of the rest of the N−1 target radio wave signals except the reference target radio wave signal based on the two difference values, and transmit the information to the device logic circuit 301. The device logic circuit 301 in FIG. 3 may use the transmitted information to calculate the ratio information about the phase signal and the signal strength of the different number N of target radio wave signals. Also, the device logic circuit 301 may determine whether the ratio information about the detected number N of target radio wave signals matches the reference ratio information, which is the ratio information about the phase signal and the signal strength allocated for the control of initially different number N of radio wave signals. The operation may be determined as normal if the existing ratio information and the calculated ratio information match and be determined as abnormal if the existing ratio information and the calculated ratio information do not match.

FIG. 5 is a diagram describing an order by which a radio wave signal is input to a radio wave signal comparator according to an example embodiment.

The operation and order of one period of an input of the radio wave signal comparator by the flow of time in an example embodiment of FIGS. 3 and 4 may be as illustrated in FIG. 5. The input of the radio wave signal comparator may be controlled by switches. The reference target radio wave signal So may be input to the radio wave signal comparator during the entire period, and the rest of the target radio wave signals except the reference target radio wave signal may be sequentially input in the current period. That is, only the target radio wave signal S₁may be selected to be input to the radio wave signal comparator during time t₁, and only the target radio wave signal S₂may be selected to be input to the radio wave signal comparator during −₂-t₁, and only the target radio wave signal S₃may be selected to be input to the radio wave signal comparator during −₃-t₂. Sequentially proceeding in such a way, only the target radio wave signal SN may be selected during t_N-1-t_N-2to be input to the radio wave signal comparator. The period may be repeatedly performed during the operation of the heat treatment device, with the input of all N−1 target radio wave signals to the radio wave signal comparator as one period.

FIG. 6 is a diagram illustrating a configuration of a heat treatment device according to an example embodiment.

Referring to FIG. 6, the heat treatment device 600 may include a radio wave signal generator