Three-Door Interlocking System – SM3C

  • Model: SM3C
  • Lock – Door: 3
  • LED indicators: 3
  • Cables: 4M
  • Material: Inox

The interlock is an auxiliary device designed to ensure that the doors of a room cannot be opened simultaneously, thereby ensuring isolation between the clean room area and the non-clean area.


  • Installed in the control room of clean rooms, buffer rooms, airlocks, intermediate rooms, changing rooms using signaling systems in the fields of healthcare, laboratories, pharmaceutical manufacturing, electronics, semiconductors, office spaces, etc.
  • Used for entrance doors, emergency exit doors, safety doors, etc.


  • Control device

  • Mechanical lock or electronic lock


  • When one door opens, the other two doors will automatically close, and all three doors cannot be opened simultaneously.
  • If one door remains open for an extended period without closing, an alarm bell will ring as a reminder to close the door, or the other two doors will automatically close.
  • In the event of a power failure, for electronic interlocks, all three doors can be opened to ensure user safety.
  • In emergencies, you can press the emergency button to force the doors to open.


  • The interlock control unit is mounted on the ceiling panel and connected to an available power outlet (the shorter the distance between the control unit and the outlet, the better, to save wiring costs).
  • Signal indicator lights are mounted on the wall panel in areas easily visible when entering/exiting, typically placed beside the panel door.
  • The lock bolt is installed underground inside the door frame (requires drilling and underground wiring) and can be installed on the side or top of the door frame.
  • The bolt positioning plate is attached to the door leaf corresponding to the lock bolt installation area.

Sangma interlocks from VCR are currently installed in pharmaceutical factories such as Merap, Hanvet, Anvy, Nam Ha.

Additionally, there are some installation errors to be aware of, such as:

  1. Ensure tight connection of signal wires to the lock bolt and signal indicator. Error: The alarm will sound loudly and continuously.
  2. Install the lock bolt and bolt positioning plate in the same direction (Wi-Fi symbol) on both accessories. Error: The lock will not function.
  3. Do not reverse the signal wires between the indicator and the lock bolt. Error: Cannot be installed. The signal wire of the lock bolt is usually slightly larger than the wire of the indicator, so please pay attention during installation.
  4. Use wire boxes and tubing to protect signal wires on the ceiling, preventing insects from biting or damaging the wires. Signal wires are different from power wires, and if they are cut or damaged, they are difficult to reconnect.

Actual images and videos

Lock installed at Merap Pharmaceutical Factory


Lock installed at Anvy Pharmaceutical Factory

Choose the interlock that suits your clean room.


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