Difference between high and low temperature test chamber and low temperature chamber

　这一难题常常会出現，依照国家行业标准而言只讲高温试验箱，由于低温箱算作高低温试验箱的一个变异支系。

　　从两者实验主要用途上开展差别：

① The main purpose of the high and low temperature test chamber is to test the high and low temperature resistance characteristics of commodities. The comprehensive statement of scientific research is: according to the pre-set standard value, then carry out high temperature experiment and ultra-low temperature experiment on the other half of the detection.

② The main purpose of the low temperature box: it is used for ultra-low temperature reliability testing, rather than high-temperature experiments.

However, there are three levels of difference between the two in terms of their principles and components: the heating system software of the refrigeration unit of the automatic control system. I think not only the high and low temperature test chambers have heating system software, but also the low temperature chambers have heating system software. For example, if an ultra-low temperature point is made within the scope marked on the factory nameplate of the environmental test chamber, the refrigeration unit must be turned on if the temperature exceeds the limit, but if the temperature exceeds the limit of ± 0.6 ℃ required by the national standard, the automatic control system must be assisted by the heating system software.

The basic principle of refrigeration is to use the balanced temperature control (BTC) method. That is, under the condition that the refrigeration unit is in continuous operation, the automatic control system operates the supply quantity of the electric heater according to the set temperature point and the results of PID full automation and operation output, and finally exceeds this stable balance. Therefore, as a whole, the refrigeration unit of the automatic control system of the high temperature test chamber and the high and low temperature test chamber (the temperature controller of the low temperature chamber is set at a lower limit of the measuring range of some enterprises) is the same, and sometimes the difference in the heating system software is only the size of the output power.