What does DMT mean on weak paper? What is the actual function?

In weak current drawings, DMT is the linkage device of normally open fire doors and the magnetic release device of electric doors.

The function is to ensure the smooth closing of the fire door. At ordinary times, the power supply is always 24V, which can keep the fire door open at 0- 150 degrees. In case of fire, the automatic door closes the fire door and provides feedback signal to the control room. There is also a linkage function: power is often used at ordinary times, and the door is closed when power is cut off. Feedback function: contact signal, indicating whether the fire door is closed. At the same time, it has buffering function to ensure the smooth closing of the fire door.

Extended data

Other symbolic meanings

1, t stands for weak current, SC20 stands for steel pipe with a diameter of 20, and FC stands for underground or underground laying.

2.T stands for weak current, D stands for strong current (usually there is no such expression as T+D), and SC20 stands for steel pipe with a diameter of 20.

3.S-5 is a steel pipe with a diameter of 15.

4.TC means ordinary carbon steel conductor sleeve laying.

5.TG: dimmer switch.

6.TF: fire control valve.

7.TN: protection is connected to zero.