The performance measurement method of the high and low temperature test chamber is divided into 5 points:

1. The environment of the test area: The environment around the high and low temperature test chamber can affect the conditions in the test chamber. The performance of the test chamber should be determined under standard atmospheric conditions. The following requirements should be considered: surrounding use conditions, should not be directly exposed to sunlight, should not be exposed to electromagnetic interference environment, should be placed horizontally, should be rotated in a place not disturbed by mechanical vibration and acoustic vibration, and the test chamber manufacturer's recommendations on power and environmental conditions should be considered. For details, please refer to the "Site Confirmation Letter" issued by Hengtai Fengke Company.

2. Temperature measurement system: The uncertainty of the measurement system measurement result is determined by the calibration of the system. Generally speaking, the sensor should be a resistance type or a thermocouple type. The 50% response time of the sensor in the air should be between 10s-40s, and the response time of the entire system should be less than 40s.

3. Test load of high and low temperature test chamber: We will have notes in all technical data (the following technical indicators are measured under no-load conditions). If the test chamber cannot be completely empty, it should be recorded. Whether the sample under test in the chamber has heat generation, weight, quantity, placement density and arrangement order will have an impact.

4. Installation of temperature sensors: The temperature measurement sensors are located in each corner of the test chamber and the center of the working space. We have a nine-point inspection standard for factory inspection in the industry, so at least 9 sensors should be placed in the chamber. For high and low temperature test chambers above 2000L, sensors should be placed in front of the center of each chamber wall (considering the large space in the chamber, at least 15 sensors should be placed in the chamber to achieve accurate uniformity). The placement of the measurement system should not affect the temperature distribution of the unloaded test chamber, and should be able to record the actual arrival temperature. For the confirmation detection system, data should be recorded at least once a minute, and the data recording device of the chamber monitoring sensor should be independent of the chamber control system.

5. Temperature performance measurement: After the chamber is stable, the actual temperature, temperature fluctuation and temperature gradient of the working space are confirmed according to the measurement results of the measurement system, and the uncertainty of the temperature measurement system should be considered.

Appendix: In order to determine the temperature change rate, the test chamber should be adjusted to the lowest specified temperature or the highest specified temperature, and the time for the temperature to rise from the 10% temperature point to the 90% temperature point in the temperature range should be monitored. After the test chamber is stabilized, the test chamber should be adjusted to the lowest specified temperature, and the time for the temperature to drop from the 90% temperature point to the 10% temperature point in the temperature range should be monitored. This is what we often call the temperature rise and fall speed (the average value of the entire process is taken here). A linear temperature rise and fall of 1-20 degrees/min can also be formulated according to user needs (the professional term in the instrument setting is "slope").