Lab
# 5 Bank
Alarm
In this experiment the student will design and implement an alarm system for a bank as specified below. The alarm is controlled by the following inputs.
There is a Special-Switch, which the watchman turns off this switch before opening the door in the morning. When the door is opened a Micro-Switch turns on and if the Special-Switch is not turned off before opening the door, the alarm will sound. When the bank is closed, the Special-Switch is turned on manually after the door is shut.
At 8 PM a Time-Switch is turned on automatically. If anyone opens the bank vault when the Time-Switch is on, the alarm will sound. The Time Switch is turned off automatically at 8 AM.
There are two keyed switches to the vault door (Vault-Switch 1 and Vault-Switch 2). Both switches must be turned on simultaneously to open the vault door. If one switch is activated alone, the alarm will sound. In other words, both of these switches must always be on or off together or the alarm will sound.
The Janitor or watchman may enter the building between 8 PM and 8 AM without causing the alarm to sound if they have the key to open the from door and a special key to turn off the Special-Switch. However, if anyone tries to open the vault between 8 PM and 8 AM, the alarm will sound.
Inputs to the logic function are:
Switches |
Assignments |
Time-Switch |
A |
Front door Micro-Switch |
B |
Front door Special-Switch |
C |
Vault-Switch 1 |
D |
Vault-Switch 2 |
E |
Procedure: