Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 167)

10 Chapter
10–1
Using Math Instructions
This chapter contains general information about math instructions and
explains how they function in your logic program. Each of the math
instructions includes information on:
•
what the instruction symbol looks like
•
typical execution time for the instruction
•
how to use the instruction
•
how to enter the instruction
In addition, the last section contains an application example for a paper
drilling machine that shows the math instructions in use.
Math Instructions
Mnemonic
Function
Code
Name Purpose Page
ADD 80 Add Adds source A to source B and stores the result in the destination. 10–4
SUB 81 Subtract Subtracts source B from source A and stores the result in the destination. 10–5
MUL 82 Multiply Multiplies source A by source B and stores the result in the destination. 10–8
DIV 83 Divide Divides source A by source B and stores the result in the destination and the
math register. 10–9
DDV 84 Double Divide Divides the contents of the math register by the source and stores the result in
the destination and the math register. 10–10
CLR 85 Clear Sets all bits of a word to zero. 10–11
SQR 86 Square Root Calculates the square root of the source and places the integer result in the
destination. 10–11
SCL 87 Scale Data Multiplies the source by a specified rate, adds to an offset value, and stores the
result in the destination. 10–12
These instructions perform the familiar four function math operations. The
majority of the instructions take two input values, perform the specified
arithmetic function, and output the result to an assigned memory location.
For example, both the ADD and SUB instructions take a pair of input values,
add or subtract them, and place the result in the specified destination. If the
result of the operation exceeds the allowable value, an overflow or underflow
bit is set.
Since these are output instructions, they do not have LD, AND, and OR
equivalents.
To learn more about the math instructions, we suggest that you read the Math
Instructions Overview that follows.
About the Math Instructions