Passive Infrared detection is the most widely used technology in security motion sensor devices. Passive Infrared motion detectors sense infrared energy (heat) and then trigger an action. The heat can be generated by a person, animal or other heat sources.
For a recent motion sensor application (the same assisted living facility job as outlined in the Door Operators: Opening The Door To New Revenue Streams article in this issue of Locksmith Ledger), we installed the Securitron XMS, a passive infrared motion detector which is specifically designed to provide free egress through a door controlled by a magnetic lock. It is designed for indoor use, and it does not offer directional detection. The XMS provides a cost effective and reliable solution for most applications.
The XMS has several specific features for door controls of this type:
The lock control function is fail safe so that the magnetic lock will safely release if power is cut to the detector.
The XMS has a form ‘C’ dry output for a REX (request to exit) signal to an access control system (if one is present) or to shunt out a DPS (door position sensor) if one is being used.
The XMS has a time extension feature which keeps the XMS unlocked and prevents resetting if the person egressing pauses before leaving.
The XMS lensing system permits the exit detection pattern to be tightly controlled to allow for maximum security and detection.
We positioned the XMS directly over the door near the latch edge of the door. Since the door is on a hallway, we aimed the XMS almost directly down, so as to not detect people passing by in the hall.
The XMS provides two means of adjustment. First, the entire barrel assembly rotates 90 degrees so that the unit can look “out” or “down.” In addition, aiming screws are provided to laterally control the pattern.
In most applications, the unit is set to look “down.”. The exception would be if the XMS was mounted on a wall perpendicular to the door rather than parallel to it. As the detection pattern proceeds outward from the XMS, it spreads. The pattern will spread out roughly three feet by the time it reaches the floor. Maximum detection distance is approximately 20 feet.
We used a filtered and regulated linear power supply with a 12 VDC output for our maglock and all the other devices. We used 12 volts because the maglock which was already on-site was an older Securitron 12-volt version. Current Securitron maglocks are auto-sensing and will operate on 12 or 24VDC.
The XMS can be operated with voltage between 12 and 28 volts DC. Power consumption for the XMS is approximately 20 mA.
Continuous power is provided to the motion sensor, the exit button, and the keypad, since when the XMS is first powered, it performs a self-test and also permits the XMS to adjust itself to the thermal environment that it “sees.” During self test the LED flashes twice quickly every second for about 40 seconds. During this start up, the XMS does not detect movement.
After this start up period, the XMS stabilizes and is ready for service. In the event of a very brief power outage, the unit will not repeat the 40 second self test but will undergo a self test of 10 seconds before resuming normal operation.
The EEB-2 EXIT Switch also cycles through a 30-second warm-up when power is applied. The ESSEX keypad comes up ready to go after a few seconds. But none of this equipment thrives on frequent power interruptions and so switching the power with the DT-7 timer would be disruptive to the systems’ operation and the client would not be happy.
The XMS has a special circuit for controlling the maglock which uses an internal field effect transistor which does the actual switching. This prolongs the life of the XMS by avoiding the wear and tear on the contacts if a conventional relay were used. Additionally not having a relay keeps the size of the XMS small, current draw lower, and as mentioned, still provides for the failsafe operating feature.
The most challenging part of designing and selling access controls systems is custom fitting systems to each client’s precise requirements.
Securitron Magnalock Corp. has developed more than 25 packaged electronic access control systems for controlling from one to three doors. These packaged electronic systems include the lock(s...