Allen Bradley Bitwise Logical Operations

To study the working of Allen Bradley Bitwise logical operations like AND, OR, NOT, XOR in Programmable logic Controllers (PLC).

Bitwise Logical Operations

Block Name: Bitwise AND

In the above picture, there are totally three parameters,

SOURCE A – Address of First Binary Value

SOURCE B – Address of Second Binary Value

DESTINATION –AND operation result of Source A & B stored in this address

Block Name: Bitwise OR

In the above picture, there are totally three parameters,

SOURCE A –Address of First Binary Value

SOURCE B –Address of Second Binary Value

DESTINATION –OR operation result of Source A & B stored in this address

Block Name: Bitwise XOR

In the above picture, there are totally three parameters,

SOURCE A –Address of First Binary Value

SOURCE B –Address of Second Binary Value

DESTINATION –XOR operation result of Source A & B stored in this address

Block Name: Bitwise NOT

In the above picture, there are totally two  parameters,

SOURCE -Address of Binary Value

DESTINATION –NOT operation result of Source stored in this address

PLC LADDER EXAMPLE

CASE 1:

When,

Source A : 0000 0000 0000 0000 (AND,OR & XOR)

Source B : 0000 0000 0000 0000 (AND,OR & XOR)

Source  : 0000 0000 0000 0000 (NOT)

Rung 0000:

All Bitwise operator block are connected in parallel with input condition I: 0/0. When it goes ON, each block performs its operation. Since Source addresses are having zeros except NOT block remaining blocks are resulting 0s.

BITWISE Operation of AND, OR, XOR, NOT:

AND Logic:

Source A : 0000 0000 0000 0000   (B3:0)

Source B : 0000 0000 0000 0000   (B3:1)

Destination : 0000 0000 0000 0000   (B3:2)

OR Logic :

Source A : 0000 0000 0000 0000   (B3:0)

Source B : 0000 0000 0000 0000   (B3:1)

Destination : 0000 0000 0000 0000   (B3:3)

XOR Logic :

Source A : 0000 0000 0000 0000   (B3:0)

Source B : 0000 0000 0000 0000   (B3:1)

Destination : 0000 0000 0000 0000   (B3:4)

NOT Logic :

Source: 0000 0000 0000 0000   (B3:0)

Destination : 1111 1111 1111 1111  (B3:5)

DATA FILE FOR CASE 1:

CASE 2:

When,

Source A : 0010  0101 0100 0001   (AND,OR & XOR)

Source B : 0001 0001 0001  0001  (AND,OR & XOR)

Source  :0101 0100 1000 0111 (NOT)

Rung 0000:

I:0/0 giving input condition to all Bitwise Blocks. When it goes ON, value placed in Source A and Source B performs respective operation depends on blocks.

BITWISE Operation of AND, OR, XOR, NOT:

AND logic:

Source A : 0010  0101 0100 0001   (B3:0)

Source B : 0001 0001 0001  0001  (B3:1)

Destination : 0000 0001 0000 0001  (B3:2)

OR Logic:

Source A : 0010  0101 0100 0001   (B3:0)

Source B : 0001 0001 0001  0001  (B3:1)

Destination : 0011 0101 0101 0001  (B3:3)

XOR Logic:

Source A : 0010  0101 0100 0001   (B3:0)

Source B : 0001 0001 0001  0001  (B3:1)

Destination : 0011 0100 0101 0000  (B3:4)

NOT Logic:

Source: 0101 0100 1000 0111 (B3:0)

Destination : 1010 1011 0111 1000  (B3:5)

DATA FILE FOR CASE 2:

Conclusion:

We can use this explanation to understand the working of Bitwise logical operation like AND, OR, NOT, XOR in Allen Bradley Programmable logic Controllers (PLC).

Author : Hema Sundaresan

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