Method for collecting temperature of visokofrekventna oprema za kaljenje

High-frequency quenching equipment heats small workpieces, from room temperature to 900° high-frequency heating, generally less than 10 s, and the time is very short. Therefore, the response speed of the sensor is particularly high, and the response time must be controlled within 200 ms, otherwise the error will be relatively large. Since the thermal conductivity of the contact sensor is relatively slow and has obvious hysteresis, it is not suitable to be used. Considering the cost performance of infrared and optical fiber non-contact temperature thermometers, the German Optris infrared thermometer CTLT20 was finally selected, its range: -40 ℃ ～900 ℃, response time: 150 ms, error 1% Within this, the thermometer has been linearly compensated, and the linearity is good, which can better realize the temperature collection.

The output of the infrared thermometer is an analog quantity of 0～10 V or 4～20 mA. First, set the corresponding relationship between the analog quantity and the digital quantity, that is, the minimum value of the analog quantity corresponds to the minimum value of the temperature measurement range of the thermometer. The maximum value corresponds to the maximum value of the temperature measurement range of the thermometer; then the A/D module of the PLC is used to collect the temperature to obtain the temperature value of the digital quantity; finally, judge whether the set temperature value is reached in the PLC program, and execute the corresponding action At the same time, the corresponding temperature value and action information are displayed on the display screen in real time.