How does Door Frame Metal Detector Work? DFMD Types Explained

Those who visited airports, train stations, government offices, shopping malls, theatres, and events would have passed through this security equipment to prove they were not carrying any metal objects. This security device is known as a “Door Frame Metal Detector.” This security technology enables security officers to inspect individuals entering a building for metal or potentially dangerous objects. Metal Detectors, like baggage scanners and CCTV cameras, are safe and effective.

Metal detectors for door frames employ pulse induction technology. This Pulse Induction method transmits short, strong current pulses across the wire coil. The impulse produces a brief magnetic field. When a particle of metal passes through this magnetic field, a reflected magnetic field will emerge, and this reflected magnetic field will interact with the reception coil, causing the door frame metal detector to sound an alert. This operation will take a few microseconds to complete. This current is known as reflected pulse and has a duration of around 30 microseconds.

Typically, PI-based metal detectors emit 100 pulses per second, however this figure can range from 25 pulses to over 1,000 pulses per second depending on the brand and type. Door frame metal detectors generate magnetic fields that permeate the whole interior space of the metal detector. If a person passes through the metal detector and the alarm sounds, airport security is notified that he or she may be carrying a dangerous metal-based weapon, such as a knife or a gun, and directed to conduct a more thorough search.

The most advanced metal detectors have numerous zones that not only sound an alarm but can also discover buried metal objects. The multi-zone door frame metal detectors contain multiple magnetic coils that generate a separate detecting zone. They can identify many objects simultaneously and reveal all hiding locations. Latest door frame metal detectors are available in up to 33 zones. The alarm lights on the side of the metal detector make it much easier for security officers to locate anything that have been concealed.

The most up-to-date door frame metal detectors have several detection zone detectors that allow them to examine the metal location that triggered the alert. This version has proven to be a secure and efficient way to maintain security.


Different Types of Door Frame Metal Detector (DFMD)

There are two different types of door frame metal detectors (DFMDs) exist:

  1. Single zone DFMD
  2. Multi-zone DFMD provide multi-zone detection

A Multi-zone DFMD (door frame metal detectors)  will determine if the target is on the left or right side of the individual. If a person walks through the DFMD (door frame metal detectors) while carrying a concealed weapon around their ankles, both the single and multi zone DFMD (door frame metal detectors) will detect the target. Multi-zone DFMD differs from Single-zone DFMD in that it may determine the target’s location on either the left or right side of the individual.

Multi-zone technology distinguishes small pistols from innocuous objects such as keys and coins.

Multi-zone The Continuous Wave Multiple Sensor Measurement Technique is favoured by DFMD over the Pulse Induction approach. This enhances screening efficiency and reduces operating expenses. Multiple zones of detection enable the precise localization of concealed weapons. 

A display indicates whether a weapon is on the left, right, or centre of the individual being screened, as well as whether it is at ankle, knee, waist, chest, or head height. If many weapons are carried, each is detected and its location is displayed. During the subsequent manual search, security professionals can immediately zero in on the offending object or objects (s.).

Horizontal multiple zone technology is distinguished by its ability to effectively distinguish between small pistols and innocuous things. Those who are being screened can pass past the detector without having to empty their pockets of the usual quantity of keys and coins. Using a single operating mode, weapons made from steel, various grades of stainless steel, aluminium, zinc alloys, and mixed alloys are detected.

The system provides superior resistance to electrical interference, hence eliminating false alarms that impede traffic flow. Additionally, the technology is continuously active, preventing weapons or contraband from being transferred, slid, or thrown through the detector undetected.

Related Posts

Generic placeholder thumbnail

Contact Us

Generic placeholder thumbnail

HOUSYS:: Security Access Management | Automation Solutions

Generic placeholder thumbnail

Perimeter Protection System

Generic placeholder thumbnail

Pedestrian Management System

Generic placeholder thumbnail


Generic placeholder thumbnail


Generic placeholder thumbnail


Generic placeholder thumbnail


Generic placeholder thumbnail


Generic placeholder thumbnail

Baggage Scanner

About Author