ACCESS CONTROL SYSTEMS
ELECTROMAGNETIC ANTI-PIGGYBACKING DEVICE (EMAD)
INFORMATION ABOUT EMAD
There is a range of important situations when it is necessary to manage large people flows and direct them from one operating zone to another one and when it is strongly undesirable to spend time and money to perform preliminary weight measuring and weight coding into access cards. EMAD has been developed to decide such tasks.
EMAD has been developed as anti-piggybacking tool for an Access Cabin for operating without preliminary information about man body in his access card and for the purpose of reduction in the cost of an Access Cabin.
THE PRINCIPLE OF OPERATION
EMAD functions in the following way: when human body is in the space filled with quasistationary electromagnetic field created by field- forming unit called Helmgolts rings and special potential electrodes, the interaction between electromagnetic field and human body results in that EMAD produces electric signals depending on body mass and biological tissues electromagnetic characteristics. These signals define human body magnetic and elecric weights..
We investigated that magnetic weights adding rule differs from electric weights adding rule for group of people in the cabin. On the base of this fact we have developed the algorithm and computer program to determine one or more than one man presents in the cabin in definite time without preliminary recording information into man's access card.
THE HUMAN BODY MAGNETIC AND ELECTRIC WEIGHTS STABILITY
We have determined that human body magnetic and electric weights stability is not worse than usual human body weight stability.
INTEGRATING IN ACCESS CABIN EMAD ALLOWS TO PERFORM NEXT FUNCTIONS:
1. By noncontact induction method EMAD allows to determine man “magnetic weight” and “electric weight” - get electric signals depending from man body mass and electromagnetic characteristics of man body (m - magnetic penetrability, e - electric penetrability, s - electroconductivity).
2. Without preliminary information about man body characteristics in his access card EMAD allows to determine absence of man, presence one or more than one man in Access Cabin.
The basic parts of EMAD are:
magnetic field- forming Helmgolz rectangular rings (dimensions 2.2´1.0´1.0 m),
electric field- forming potential electrodes (dimensions 2.2´1.0´1.0 m),
the measuring unit (dimensions 150´70´30 mm).
PROFITS FROM REPLACEMENT OF EWD WITH EMAD
In case of using the electromechanical weighing device (EWD) as an anti-piggybacking tool in Access Cabin the entire module with closed doors and man inside is weighed. Such Access Cabin construction must provide independent man weight measuring results from man place in cabin. It leads to increasing of cabin construction cost by dozens of percentages.
The Access Cabin construction is simplified sharply in case of EWD substitution for EMAD. The construction of Access Cabin will be similar to empty box with two doors in this case.
But there are some additional requirements on cabin construction using EMAD. It must not include determine oriented short-circuit metal loops and metal planes with large surface; cabin metallic parts should not move linear or progressively during EMAD measuring the man magnetic weight (cylindrical metallic parts rotation around own axes does not influence on EMAD work).
These requirements can be performed with minimal expanses (e.g. dissection of door metal frames formed closed electrical rings, replacement of some metal parts with dielectric ones, measurements using time gating etc.).
Obviously EWD substitution for EMAD will provide large economic effect by dozens of percentages of cabin construction cost.
EMAD has longer work period, is more reliable, repairable and suitable in exploitation in comparison with EWD.
EMAD BASIC TECHNICAL CHARACTERISTICS
Maximum induction affecting on man is no more than 10-8 T when he is in the middle of the cabin and no more than 10-7 T when he is at the door inside the cabin.
Maximum electric field intensity affecting on man is no more than 1 V/m when he is in the middle of the cabin and no more than 10 V/m when he is at the door inside the cabin.
|Velocity range||6...8 persons per minute|
|Magnetic/electric weight measuring error||no more than 10 %|
|Magnetic/electric weight measuring time||2 s|
|Temperature range||+10 ... +40 °C|
|Relative air damp||no more than 95% at 20 °C|
|Power consumption||no more than 10 W|