Allen Bradley Math Functions

To study the working of Allen Bradley Math functions (ADD, SUB, MUL, DIV, SQR & NEG) using simple example in programmable logical controllers (PLC).

Contents

There are three parameters in each block,

Source A –Address of the first Value

Source B –Address of the second value

Destination (Dest) – Address where result of the function will store.

PLC Math Functions

ADD:

Add block is used to do the Addition of the two values stored in source A and source B and store the output in destination address.

SUB:

Sub block is used to do the Subtraction of the two values stored in source A and source B and store the output in destination address.

MUL:

MUL block is used to do the Multiplication of the two values stored in source A and source B and store the output in destination address.

DIV:

DIV block is used to do the Division of the two values stored in source A and source B and store the output in destination address.

SQR

SQR block is used to find the square root of the value stored in source address and results the value in destination address.

NEQ:

NEQ block is used to negate the value stored in source address and results the value in destination.

Program Logic

When start switch is pressed,

Value stored in N7:0 and N7:1 gets added and results the value in N7:2
Add block output is one of the input to Sub block which do subtraction function by taking value stored in N7:1 and stores the address in N7:3.
Sub block output is one the input to Mul block and perform multiplication along with value stored in N7:1 and stores the result in N7:4
Mul block output is one the input to DIV block and perform Division along with value stored in N7:0 and stores the result in N7:5
SQR block performs square root of the Value stored in N7:5 and results the output in N7:6.
Value stored in N7:6 get negated using NEG block and results the final output in N7:7.
If the resulted output is positive turn on output positive indication else output negative indication.