26-06-2014, 11:03 AM
Multiprocessor Security System using CAN Bus Communication
Multiprocessor.docx (Size: 374.54 KB / Downloads: 14)
Multiprocessor Security System using CAN Bus Communication
This multiprocessor security system is developed with CAN bus module designed as a general purpose controller. This same CAN bus module can be placed at any point in the security system that requires a controller and communication between controllers. This will enable any station to communicate with other station without putting too much load to the main controller.
The project goals are: a more flexible, more economical, easier to maintain, increase in reliability while keeping the low cost in manufacturing.
System Built Up.
The overall security system is based on the integration of several subsystems.
There are several considerations which are required in the construction of a security system. Refer Figure 1 : Security System Block Diagram.
Main Controller Unit :
responsible to monitor the secure premises, control the operation of the overall system, indicate zone status and authorize legal entries as well as to trigger the alarm. The design requires a +5V to drive to microcontroller and indicator circuit while a +12V supply is used to drive the Alarm Unit, power connected nodes, activate the door solenoid as well as monitor the sensor network. Both voltage supplies are rated at 1A maximum. The design includes a backup battery supply with an onboard trickle-charger to provide a constant 13.85V to charge any 12V sealed lead acid battery. However, a 7AH battery is recommended to power the overall security system in case of power failure. A fully charged battery can last up to approximately 13 hours at minimum power consumption.
Keypad Node :
a module used to interface the Primary Base Terminal with a 4x4 matrix keypad. The matched module is responsible to accept key press entries which is then transmitted via CAN Bus to the Main Control Unit. Received data is then compared with related codes (either pass code or master code) before it replies with a certain address and 64-bit data pattern. Related nodes will then respond accordingly to the received data.
Door Strike node :
used for acceptance response, solenoid actuation, CAN Bus check responds, and zone break-in detector. Zone check selector switch is used to set the node only to respond to specific address request.
Zone Sensor node : very similar in design to the Door Strike node, except that it is built without the door strike actuator. The module is used for acceptance response, CAN Bus check responds, zone break-in detector and an extra indicator LED.
Alarm or Sounder Unit :
used to house alarm and indicator devices such as main siren, strobe light, and buzzer. The triggering of the alarm unit is directly controlled by the Main Control Unit. The unit design incorporates an anti-temper circuitry counter any unauthorized attempt to open, modify or disconnect the unit and has its own internal connected backup battery.