Definition:

Temperature deviation: The upper and lower deviations between the measured maximum and minimum temperatures of each measuring point in the working space and the set temperature within the specified time in the stable state of the test chamber (chamber).

According to the definition of GB/T 5170.1 standard, the measurement of temperature deviation requires the following conditions:

1. (1) Definition of GB/T 5170.1: The state in which the self variation of any point in the working space of the test chamber (chamber) meets the performance index requirements of the equipment itself.

(2) GB/T 5170.2 indicates that the set value has been reached and stabilized for 30 minutes (with a maximum stabilization time of 2 hours).

2. (1) Regarding the number of measurement points, 5170.2 is determined based on the volume of the test chamber:

1) Less than 0.05 cubic meters, which can be less than 9 points

2) When it is less than 2 cubic meters (and not less than 0.05 cubic meters), 9 points

3) When it is greater than 2 cubic meters (but not greater than 50 cubic meters), 15 points

4) When it is greater than 50 cubic meters, there should be more than 15 measurement points

(2) Regarding the spatial distribution of measurement points, 5170.2 stipulates:

1) Divided into three layers: upper, middle, and lower

2) Each layer has one geometric center point (1 * 3=3), one point (4 * 2=8 points) at a distance of 1/10 between the upper and lower layers and adjacent box walls (both greater than 50mm and less than 500mm), and one point (4 points) at a distance of 1/10 and 1/2 between the middle layer and the box wall, i.e. 3+8+4=15 points.

3) When there is a sample rack or sample car inside the box, the measurement points on the lower layer can be placed 10mm above it.

(3) Regarding the selection of temperature values for inspection, 5170.2 specifies three situations:

1) 2423.1 (low temperature) test, -65, -40, -20, -10, 5 degrees Celsius, etc,

2) 2423.2 (high temperature) test, 30, 50125, 200250 degrees Celsius, etc,

3) User defined temperature points.

3. At the specified time (usually 30 minutes),

5170.2 indicates that recording begins when the device is in a stable state, every 1 minute, for a total of 30 times, which is 30 minutes.

4. The difference between the measured maximum temperature and the set temperature is the upper deviation.

The difference between the highest temperature measured 30 times in each measurement point and the set temperature is the upper deviation, so the prefix "+" is used.

5. The difference between the measured minimum temperature and the set temperature is the lower deviation.

The difference between the minimum temperature measured 30 times in each measurement point and the set temperature is the lower deviation, hence the prefix "-".

The upper and lower deviations can be expressed separately or together with "±". For example, temperature deviation: ± 1.5 ℃.

6. Determination of inspection results

1) 5170.2 indicates that it meets the requirements of 2423.1, 2423.2, 2423.22 or relevant standards or contracts, and is considered "qualified".

2) When some points do not meet the indicator requirements, it is allowed to appropriately reduce the working space of the equipment. After reduction, it should meet the indicator requirements and can also be judged as qualified, but it needs to be explained in the report.

The tabletop high and low temperature test chamber developed by Zonglen is an instrument and equipment that provides constant damp heat and alternating high and low temperature test environments and conditions for various industrial products in various stages of research and development, production, inspection, and testing, and tests various performance indicators. Suitable for a wide range of needs in industries such as electronic devices, electromechanical products, materials and energy, pharmaceuticals and chemicals, and automotive and aerospace. Due to its compact and delicate body, it is easy to move, and can be placed on a desktop. Multiple platforms can also be stacked and placed through a rack, fully utilizing effective space.

Features of desktop high and low temperature test chamber:

·Desktop placement

·Programmable temperature and refrigeration system program

·Continuous work for 500 hours without frost formation

·Temperature deviation: ± 2 ℃ (when the temperature is ≤ 100 ℃)

·Temperature control accuracy as low as ± 0.1 ℃

·Temperature fluctuation: ± 1 ℃

·High mute: ≤ 55db

·Network management, remote visualization and automatic control, etc