The timer is also called the time switch. It is similar to the alarm clock we use. It can be timed at different times in one day or one week. There are output contacts, such as automatic start device at 8 o'clock in the morning and automatic shutdown at 5 o'clock in the afternoon. The time relay is like a stopwatch. When the condition is satisfied, it starts to count. When the time is up, it is output, which is relative.