1. Temperature shock test and temperature change test Temperature shock test: This test is characterized by only performing initial and final testing of product performance before and after the test to determine whether the product can withstand rapid changes in temperature, and does not require the product to undergo temperature changes. Work during the process and meet the performance requirements. The high and low temperature conversion of the high and low temperature box during the test generally stipulates that the conversion time is less than 51. Temperature shock test and temperature change test Temperature shock test: This test is characterized by only initial product performance before and after the test Inspection and final inspection to determine whether the product can withstand rapid changes in temperature. It is not required that the product work during temperature changes and meet performance requirements. The high and low temperature conversion of the high and low temperature box during the test process generally stipulates that the conversion time is less than 5 minutes (this At the same time, it is also an index required for measurement). Temperature change test: A test to assess the resistance and normal working ability of the product during temperature changes. A test box is used to limit the rate of temperature change. Such as: 10℃/min 15℃/min 20℃/min2, temperature tolerance In many environmental test method standards, the test condition tolerance is an important technical index, which reflects the environmental test's control level of the equipment The requirements reflect the standardization of environmental testing. Therefore, it is of utmost importance to correctly understand the tolerances of test conditions specified by the head standard, so as to improve the reliability and scientificity of environmental test results. The national standard GB2423.1 low temperature test method stipulates the allowable temperature deviation range of ±3℃, where ±3℃ does not refer to that point or at that time, emu's requirements for all points in the entire working space. Another issue that should be pointed out is that the temperature tolerance of ±2°C is the concept of allowable deviation. When the GJB150 military standard temperature gradient is at a maximum of 2.2°C, the uniformity of the temperature field is required to be the relationship between the temperatures of various points in the temperature field at a certain instant. . The temperature tolerance of ±2°C should never be regarded as the setting range of the nominal value. Example 60±2°C where 60°C is the nominal value, and ±2°C is the tolerance. When setting the environmental condition parameter value, the temperature setting value can only be 60°C, not 62°C, or 58°C. Due to the error in the drift adjustment of the control system and the non-uniformity of the temperature field of the test chamber, the actual measurement result of the test temperature cannot be 60 ℃, and the allowable deviation but the range is not more than 62 ℃ or not less than 58 ℃ 3, in the environmental test equipment Relative humidity measurement Relative humidity is a very important parameter in environmental tests. Reasonable and accurate measurement of relative humidity is of great significance for ensuring environmental conditions. The so-called relative humidity is the ratio of the partial pressure of water vapor in the air to the partial pressure of saturated water vapor at the same temperature uu003de/es*100%. The relative humidity in the RS test box is usually unable to measure the partial pressure of water vapor and saturated water in the air. The vapor partial pressure is obtained by measuring the dry bulb temperature and converting it to eu003detw-APt-tw. The basis of measuring the relative humidity by the dry and wet bulb method is the air condition. If the relative humidity is measured by the dry and wet bulb method during the temperature change phase, it is Inaccurate, it can only be used as a reference. When the air condition is stable, the relative humidity is only affected by the value of A. Au003d0.0000165+6.75. From the formula, the value of A depends on the air velocity flowing through the wet bulb, so it flows through the wet bulb. The air velocity of the ball is an important factor that affects the relative humidity measurement. Experiments have shown that when the air velocity is greater than 2.5m/s, the impact on the relative temperature is not obvious, but the test box is under airtight conditions and requires work during verification. Multiple relative humidity measurement points are arranged in the space. In this way, in the working space generally <1 m3, there will be multiple wind sources that can generate local air speeds greater than 2.5 m/s, which will destroy the original working state of the test box, which is obviously inappropriate
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