Calibrating the temperature and humidity of a reliability environmental test chamber is a crucial step to ensure the accuracy and reliability of test results. Here are the specific methods for calibrating temperature and humidity:
I. Temperature Calibration
1. Preparation
(1) Selection of Calibration Equipment
Choose high-precision temperature measurement instruments, such as standard platinum resistance thermometers or thermocouples, whose accuracy should be higher than that of the temperature sensors in the environmental test chamber.
Choose high-precision temperature measurement instruments, such as standard platinum resistance thermometers or thermocouples, whose accuracy should be higher than that of the temperature sensors in the environmental test chamber.
(2) Inspection of the Test Chamber
Ensure that the test chamber is in good condition, with no external damage, complete internal structure, and normal operation of the power supply and control systems.
Ensure that the test chamber is in good condition, with no external damage, complete internal structure, and normal operation of the power supply and control systems.
2. Calibration Steps
(1) Placement of Temperature Sensors
Distribute the calibration temperature sensors evenly at different locations inside the test chamber, such as the upper, middle, and lower layers, as well as corners and the center, to comprehensively reflect the temperature distribution within the chamber.
Distribute the calibration temperature sensors evenly at different locations inside the test chamber, such as the upper, middle, and lower layers, as well as corners and the center, to comprehensively reflect the temperature distribution within the chamber.
(2) Setting Temperature Points
Select several temperature calibration points based on the operating range and requirements of the test chamber. These typically include low, high, and intermediate temperatures. For example, for a common high-low temperature test chamber, calibration points could be set at -40°C, 0°C, 25°C, 50°C, and 80°C.
Select several temperature calibration points based on the operating range and requirements of the test chamber. These typically include low, high, and intermediate temperatures. For example, for a common high-low temperature test chamber, calibration points could be set at -40°C, 0°C, 25°C, 50°C, and 80°C.
(3) Stabilizing Temperature
Set the test chamber to the first calibration temperature point, start the chamber, and allow the temperature to stabilize for at least 30 minutes to ensure that the temperature inside the chamber reaches equilibrium.
Set the test chamber to the first calibration temperature point, start the chamber, and allow the temperature to stabilize for at least 30 minutes to ensure that the temperature inside the chamber reaches equilibrium.
(4) Data Recording
Once the temperature is stable, simultaneously read and record the temperature values from both the high-precision calibration thermometer and the built-in temperature sensor of the test chamber.
Once the temperature is stable, simultaneously read and record the temperature values from both the high-precision calibration thermometer and the built-in temperature sensor of the test chamber.
(5) Comparison of Deviations
Calculate the deviation between the temperature displayed by the test chamber and the temperature measured by the standard thermometer at each calibration point. The deviation should be within the specified range, generally not exceeding ±2°C.
Calculate the deviation between the temperature displayed by the test chamber and the temperature measured by the standard thermometer at each calibration point. The deviation should be within the specified range, generally not exceeding ±2°C.
(6) Adjustment and Correction
If the deviation exceeds the allowable range, adjustments and corrections need to be made to the temperature control system of the test chamber to bring the displayed temperature closer to the standard value. This can be done through the test chamber's operation interface by entering the parameter settings to modify the temperature sensor's coefficient, offset, etc. Refer to the test chamber's manual for specific procedures.
If the deviation exceeds the allowable range, adjustments and corrections need to be made to the temperature control system of the test chamber to bring the displayed temperature closer to the standard value. This can be done through the test chamber's operation interface by entering the parameter settings to modify the temperature sensor's coefficient, offset, etc. Refer to the test chamber's manual for specific procedures.
(7) Repeat Calibration
After completing the calibration for all selected temperature points, run another calibration cycle to ensure the accuracy and stability of the calibration.
After completing the calibration for all selected temperature points, run another calibration cycle to ensure the accuracy and stability of the calibration.
II. Humidity Calibration
1. Preparation
(1) Selection of Calibration Equipment
Use high-precision humidity measurement instruments, such as calibrated hygrometers or dew point meters, whose accuracy should be higher than that of the humidity sensors in the test chamber.
Use high-precision humidity measurement instruments, such as calibrated hygrometers or dew point meters, whose accuracy should be higher than that of the humidity sensors in the test chamber.
(2) Inspection of the Test Chamber
Ensure that the test chamber is in good condition, with no external damage, complete internal structure, and normal operation of the power supply and control systems.
Ensure that the test chamber is in good condition, with no external damage, complete internal structure, and normal operation of the power supply and control systems.
2. Calibration Steps
(1) Placement of Humidity Sensors
Distribute the calibration humidity sensors evenly at different locations inside the test chamber, such as the upper, middle, and lower layers, as well as corners and the center, to comprehensively reflect the humidity distribution within the chamber.
Distribute the calibration humidity sensors evenly at different locations inside the test chamber, such as the upper, middle, and lower layers, as well as corners and the center, to comprehensively reflect the humidity distribution within the chamber.
(2) Setting Humidity Points
Select several humidity calibration points based on the operating range and requirements of the test chamber. These typically include low, high, and intermediate humidity levels. For example, calibration points could be set at 20%, 50%, and 80% relative humidity.
Select several humidity calibration points based on the operating range and requirements of the test chamber. These typically include low, high, and intermediate humidity levels. For example, calibration points could be set at 20%, 50%, and 80% relative humidity.
(3) Stabilizing Humidity
Set the test chamber to the first calibration humidity point, start the chamber, and allow the humidity to stabilize for at least 30 minutes to ensure that the humidity inside the chamber reaches equilibrium.
Set the test chamber to the first calibration humidity point, start the chamber, and allow the humidity to stabilize for at least 30 minutes to ensure that the humidity inside the chamber reaches equilibrium.
(4) Data Recording
Once the humidity is stable, simultaneously read and record the humidity values from both the high-precision calibration hygrometer and the built-in humidity sensor of the test chamber.
Once the humidity is stable, simultaneously read and record the humidity values from both the high-precision calibration hygrometer and the built-in humidity sensor of the test chamber.
(5) Comparison of Deviations
Calculate the deviation between the humidity displayed by the test chamber and the humidity measured by the standard hygrometer at each calibration point. The deviation should be within the specified range, generally not exceeding ±5% relative humidity.
Calculate the deviation between the humidity displayed by the test chamber and the humidity measured by the standard hygrometer at each calibration point. The deviation should be within the specified range, generally not exceeding ±5% relative humidity.
(6) Adjustment and Correction
If the deviation exceeds the allowable range, adjustments and corrections need to be made to the humidity control system of the test chamber to bring the displayed humidity closer to the standard value. This can be done through the test chamber's operation interface by entering the parameter settings to modify the humidity sensor's coefficient, offset, etc. Refer to the test chamber's manual for specific procedures.
If the deviation exceeds the allowable range, adjustments and corrections need to be made to the humidity control system of the test chamber to bring the displayed humidity closer to the standard value. This can be done through the test chamber's operation interface by entering the parameter settings to modify the humidity sensor's coefficient, offset, etc. Refer to the test chamber's manual for specific procedures.
(7) Repeat Calibration
After completing the calibration for all selected humidity points, run another calibration cycle to ensure the accuracy and stability of the calibration.
After completing the calibration for all selected humidity points, run another calibration cycle to ensure the accuracy and stability of the calibration.