Talk about the temperature deviation index of the high temperature test box

Friday,May 11 2018

1. Cause:

The calibration of test equipment, some technical indicators, and national standards of different versions are not uniform, which has caused some trouble. For example, the index of temperature deviation, JJF1101-2003 "environmental test equipment temperature and humidity calibration standard" and GB/T 5170.2-2008 "electrical and electronic products environmental test equipment test method temperature test equipment", the two standards inside the rules are different. Let's talk about temperature deviation and humidity deviation.

Two. Definition:

1. JJF1101-2003 calibration specification for temperature and humidity of environmental test equipment:

The stability of the environmental test equipment shows the difference between the average temperature and the average temperature measured at the center of the workspace. (Note: the display temperature mean here refers to the display temperature average of the device temperature control instrument).

2. GB/T 5170.2-2008 "temperature test equipment for electrical and electronic products environmental test equipment":

When the test chamber (chamber) is stable, the measuring points in the workspace measure the maximum and minimum temperature and the minimum temperature and the nominal temperature in the specified time.

Three. The main points are:

1, JJF1101-2003 "calibration standard for temperature and humidity of environmental testing equipment": the base point is the average measured temperature of the center of the working space, the object of which is to show the average temperature of the equipment temperature control instrument and check its deviation from the datum point. Obviously, this has nothing to do with temperature uniformity.

This is similar to the temperature indicator error index in GB/T 5170.2-2008, but the reference point is different. The reference point in the GB/T 5170.2-2008 is the average temperature measurement of all the measuring points in the equipment workspace.

2, GB/T 5170.2-2008 "test equipment for test of environmental test equipment for electrical and electronic products" temperature test equipment: the reference point is the nominal temperature (that is, the test temperature you want to do, generally equivalent to the set value), the assessment object is the various measurement points in the workspace (such as the small preparation is 9 test points), and the assessment of its and base The degree of deviation of the punctuality. It can be seen from this that the temperature uniformity has been included. If the evenness is not good, the temperature deviation will not be reached.

In general, the temperature deviation index is easy to implement in the case of JJF1101-2003, because it only checks the temperature average of the equipment temperature control instrument. In comparison, the implementation of the GB/T 5170.2-2008, the realization of the temperature deviation index is a little difficult, because it is to examine the various measuring points in the workspace.

Four. Implementation:

At present, the situation we have mastered, the Metrology Institute of various provinces and cities is generally carried out according to JJF1101-2003; and the aviation and aerospace military industry is generally carried out in accordance with the GB/T 5170.2-2008.