What is the linear and non-linear of temperature and humidity chamber？

What is the linear and non-linear of temperature and humidity chamber？

Linear refers to the process test of heating, cooling. Nonlinear refers to no accuracy of the heating and cooling process, as long as the desired result is achieved.

Linear test: assume heating rate / cooling rate from the temperature point A to B is set, then the realtime temperature curve strictly follows this setting for every minute, or even every second.
For example, the temperature and humidity test chamber setting heating rate is 3 degree C per minute, then the actual heating rate is always 3 degrees per minute without any change  not sometimes 2 degrees per minute, sometimes 4 degrees per minute; Similarly, the cooling speed is the same.

Nonlinear test: assuming the temperature of the test to be divided into high temperature, then normal temperature, then low temperature, Specific capable program settings, Now set the high temperature to the A point, Normal temperature is the B point, Low temperature is a C point, Program conditions: A Point Test 30 minutes → to B Point Test 30 minutes → to C Point Test for 30 minutes, The operating action status in the nonlinear setting is: reach the A point, B point, and C point at the existing setting time, The total moment of each period during the work process reaches the need, Heating or cooling process curve does not specify compliance logic. 
For example, the temperature and humidity test chamber setting heating rate is 3 degree C per minute, the actual heating rate is sometimes 3 degrees per minute, sometimes 4 long per minute, it just ensures an average of 3 degrees per minute.