Department of Engineering,
College of Engineering and Applied Sciences,
American University of Kuwait,
P. O. Box 3323, Safat, 13034
Kuwait
Programmable Logic Controller Laboratory
ELEG 301L
(Spring 2021)
Lab #4: Burglar Alarm System Using PLC
Aim
In this lab, a burglar alarm security system will be implemented using Ladder Diagram programming.
1. Problem Description
Design a burglar alarm system for a house using PLC programs. This alarm will be activated if
an unauthorized person is detected by a window sensor or a motion detector. The alarm must be turned
ON in case of any unauthorized activity, and it must keep on ringing until it is manually stopped. Provide
push buttons to activate and deactivate the system. Implement and test the system in PLC using Ladder
Diagram programming.
2. Problem Solution
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Two sensors are used, one is a window sensor and the other one is a motion detector.
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The window sensor is designed such that if the window is opened, the output of the sensor is logic
1 or high.
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The motion detector is designed such that when a person is detected, the output of the sensor is logic
1 or high.
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Two push buttons are used to activate and deactivate the system, in addition to a button to stop the
alarm.
2.1 List of Inputs and Outputs
I0.0 = Activate/MS (Input)
Q0.0 = Master Coil (Output)
I0.1 = Deactivate (Input)
Q0.1 = Alarm Coil (Output)
I0.2 = Motion Detector (Input) Q0.2 = Alarm (Output)
I0.3 = Window Sensor (Input)
I0.4 = Stop Alarm (Input)
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2.2 Ladder Diagram for Burglar Alarm Security System
Figure 1: The ladder diagram program for the burglar alarm security system.
2.3 Program Description
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Rung 1 shows a latching of a coil Q0.0 to activate the entire security system.
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When Activate button I0.0 is pressed momentarily, the security system is activated.
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If the system is not activated, alarm does not indicate anything since sensors will have no effects on
the Alarm Coil Q0.1.
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When the system is active and Motion Detector detects a person, the alarm coil will momentarily go
high activating the Alarm Q0.2 which stays ON until I0.4 is pressed manually.
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an OR operation is implemented in Rung 2 for the two sensors, which means if either of the sensors
sense an activity, the alarm will be activated.
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Latching must be provided in Rung 3 to keep the alarm ringing even if the detection by the sensors
are momentary or pulsing.
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3. Report
1. Implement the system program and include screenshots of testing it in the report.
2. Write the truth table proving the operation of the system (while activated or while not activated) and
include it in the report.
3. Draw the timing diagram of the system and include it in the report.
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