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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