Programmable Logic Controller Boolean Algebra

Programming Restrictions PLC does not allow for programming vertical contacts. PLC does not allow logic continuity (power flow) from right to left. A B C D E F A B C D E F G

A B F D C C E A B C G D E D E F E F D B C

Self Latching Circuit A B F F

Boolean Algebra The purpose of Boolean algebra is to provide a simple way of writing complicated combinations of logic statements

Gate Boolean Equations Y AND Y = A B Gate Boolean Equation OR A B Y Y = A + B NOT A Y Y = A

1. Which gate logic shown represents the Boolean equation: ( A + B ) C = Y (a) (b) (c) (d)

2. The correct Boolean equation for the combination logic gate circuit shown is: a. Y = A B C D c. Y = ( A + B ) ( C + D ) b. Y = ( AB ) + ( CD ) d. Y = ( AB ) + ( CD )

3. The correct Boolean equation for the combination logic gate circuit shown is: a. Y = ( A + B + C ) D c. Y = ( AB + C ) D b. Y = ( A + B ) ( C + D ) d. Y = ( ABC ) D

4. The correct Boolean equation for the combination logic gate circuit shown is: a. Y = A B C c. Y = A + B + C b. Y = ( A B ) C d. Y = ( AB ) + ( BC )

5. The correct Boolean equation for the ladder logic program shown is: a. Y = (A B) + (CD) c. Y = A + B + C + D b. Y = (A+B ) (C+D) d. Y = ABCD

6. The correct Boolean equation for the ladder logic program shown is: a. Y = (A B) + (CD) c. Y = A + B + C + D b. Y = AB (C+D) d. Y = ABC + D

7. If you want to know when matching bits in two different words are both "on", you would use the _____ logic instruction. a. AND c. XOR b. OR d. NOT 8. If you want to reverse the state of bits in a word, you would use the ______ logic instruction. a. AND c. XOR b. OR d. NOT

Exercise Design fire alarm system using ladder diagram.