The characteristics and components of the small temperature controller
Many industrial production, such as flower planting or small greenhouses, etc., have a high demand for temperature. At Electric Filter Fan Cabinet Heater Fan Heater with Thermostat this time, it is necessary to detect and control the temperature. Generally speaking, the traditional method is to distribute the temperature sensor simulation signal to the converter, and then use the data obtained by the single -chip microcomputer to analyze it. Finally, the corresponding processing of this analysis is taken.
1 The characteristics of the small temperature controller
The characteristics of the temperature controller are simple: there are two points:
1) The precise physical model of the system is difficult to get.
2) Non -linear, time change and lag in the system.
Under normal circumstances, if the performance of the controller is better, it can completely make up for the effects of the temperature controller, the external non -linearity of the temperature controller, and other factors; if the performance of the controller is not very good, it will appear when it appears. The phenomenon of stagnation, so that the control of temperature or the control of objects with great lag.
2 The components of the small temperature controller
1) Thermocouple. Thermocouple, the temperature detection element commonly used in the industry, has a wide range of use. Has the following advantages: ① High measurement accuracy. It is directly in contact with the object measured and is not affected by any intermediate medium. ② Wide measurement range. From -50 —+1600 ° C can be measured continuously. ③ Easy measurement. It consists of two different metal wires and is not limited by size and beginning.
Overall, thermocouple can be divided into two types: standard and non -standard. Standard refers to the relationship between the national standard and the temperature and the error, there is a relatively unified standard score table, and a supporting display instrument. There are seven standard thermocouples, which can be selected and used according to different temperature measurement range. The rest belong to non -standard types.
2) Sensor heater. The inductive heating is derived from the electromagnetic induction phenomenon from Faraday. For a long time, technicians have a good understanding of this phenomenon, and try to suppress this heating phenomenon on various occasions to reduce loss. For more common transformer design in the switch power supply, the designer usually uses various methods to reduce vortex losses to improve efficiency. However, at the end of the 19th century, the technical personnel found that the negative face of this phenomenon was to use heating occasions to replace some traditional heating methods. The use of induction heating has the following advantages: ① non -contact heating, heat source and heating objects can not be directly contact. ② High heating efficiency and fast speed can reduce surface oxidation. ③ It is easy to control temperature and improve processing accuracy. ④ Achieve automation control. ⑤ reduces land occupation, heat radiation, noise and dust.
3 The processing method of temperature data
Temperature data requires a certain amount of processing. Generally speaking, the binary temperature of the two -bytes read out of the two -bytes needs to be converted into a decimal value before the output can be displayed. In contrast, the resolution temperature of the 12 -bit is 0.0625 steps, and because the temperature of the two bytes is represented by a supplementary code, it is necessary to first judge to read the highest bit of the temperature, that is, the talent can only be possible It can be concluded whether it is positive or negative, and then the supplementary code can be turned into positive temperature. If the temperature value reads is negative, when the display is processed, the person in front of the temperature can display the negative sign. It should be noted that at the temperature of the decimal section, the 4 digits need to be multiplied at 0.0625, and then the number of digits after the decimal point is accumulated.
4 The software design of the temperature controller
The software design of the temperature controller is on a single -chip machine and it is controlled by it. The programs of the main control include: initialization; keyboard display management; calling for each subroutine. The resistance value of platinum resistance is not exactly linear as its temperature. It is because of this that it is designed to design non -equilibrium segmental risk interpolation lines to compensate the platinum resistance.
5 temperature control mode
Relatively speaking, manual control will look easier, but this manual control is often high for operators. Generally speaking, the operator should combine the relationship between operating experience and voltage in accordance with various requirements in the process formula table. Of course, this relationship is usually corresponding to the relationship. Automatically pass the control of the operator’s control requirements to the inductive heater to achieve temperature control. Relatively speaking, the manual control mode has obvious disadvantages. At this time, it needs to be automatically controlled by temperature, and according to this calculation of the variables in the middle of the climbing step, the voltage value is gradually adjusted to the expected value. Compared with the temperature error of the detected actual temperature, when the temperature error is small to a certain value, enter the temperature closed -loop control.