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Time relays are divided into two types: on-time delay type and off-time delay type, and their symbols are shown in the following figure. For the power-on delay type time relay, when the coil is powered on, the power-on delay type contact acts after the delay time (the normally closed contact is opened and the normally open contact is closed), and the contact immediately returns to normal after the coil is powered off; For the power-off delay type time relay, when the coil is powered on, the power-off delay type contact acts immediately (the normally closed contact is opened and the normally open contact is closed). After the coil is powered off, the contact will not return to normal until the delay time is passed.这比一直一贫如洗还难受。4. Obtain process instances and tasks according to business keys5. At the same time, press and hold the volume reduction key on the left side of the mobile phone;红椒等人心虚，耐心地跟他再解释。