Programmable constant temperature and humidity test machine, the number of programs that can be used: maximum 120 groups, 1 program can be composed of 1 to 100 segments, a total of 1200 segments; can repeat the command: each command can be up to 999 times, the program slope setting can be set by the time axis, the maximum setting of each segment between programs is 99 hours and 99 minutes, the minimum is one minute, and can be set for connection use.