Copyright © 2002 Delmar Thomson Learning Chapter 4 Number Systems
Copyright © 2002 Delmar Thomson Learning Objectives Identify the commonly used number systems used in PLCs. Convert binary data to decimal. Examine how data is stored in PLC data tables. Describe how BCD field devices interface.
Copyright © 2002 Delmar Thomson Learning Why Do I Need to Understand How Data Is Represented? In order to install, program,maintain, and troubleshoot today’s PLCs, you must understand the different methods by which internal data is represented.
Copyright © 2002 Delmar Thomson Learning Number Systems Typically Used with PLCs
Copyright © 2002 Delmar Thomson Learning We Use Words to Represent Information Our words are groups of characters grouped together to represent something. The words we use are of different lengths: Controller The Monday
Copyright © 2002 Delmar Thomson Learning We Use Symbols Called Numbers to Represent Data Everyday numbers are decimal. 12,345
Copyright © 2002 Delmar Thomson Learning Computers Do Not Understand Computers do not understand the words and numbers humans use. Computers have their own language called binary.
Copyright © 2002 Delmar Thomson Learning Binary Language Binary information is also represented in groups of characters. A group of BInary digiTs called bits can be organized into words. Binary bits consist of only two characters: 1 and 0
Copyright © 2002 Delmar Thomson Learning Binary Words 16 bits grouped together is called a word. A binary would might look like:
Copyright © 2002 Delmar Thomson Learning Decimal Numbers Ten Digits 0,1,2,3,4,5,6,7,8,9 Base or radix 10 Weights 1, 10, 100, 1000 …..
Copyright © 2002 Delmar Thomson Learning Decimal Number System
Copyright © 2002 Delmar Thomson Learning Sixteen-Bit Binary Word Bit Weighting
Copyright © 2002 Delmar Thomson Learning Comparison of Decimal to Binary Numbers
Copyright © 2002 Delmar Thomson Learning Decimal Place Value Equivalent
Copyright © 2002 Delmar Thomson Learning Comparison of Decimal to Binary Numbers
Copyright © 2002 Delmar Thomson Learning Four-Digit BCD Thumb-Wheel
Copyright © 2002 Delmar Thomson Learning Comparison of BCD to Decimal and Binary Numbers
Copyright © 2002 Delmar Thomson Learning Single-Digit BCD Thumb-Wheel Interfaced to a PLC
Copyright © 2002 Delmar Thomson Learning Binary-Coded Decimal Number Bit Patterns
Copyright © 2002 Delmar Thomson Learning Two-Digit BCD Thumb-Wheel Interface
Copyright © 2002 Delmar Thomson Learning BCD Invalid Codes
Copyright © 2002 Delmar Thomson Learning Thumb-Wheel Dialed to 11
Copyright © 2002 Delmar Thomson Learning Thumb-Wheel Dialed to 743
Copyright © 2002 Delmar Thomson Learning Output Module Connected to Seven-Segment Display
Copyright © 2002 Delmar Thomson Learning Decimal 0 through 7 Represented with Binary Bits
Copyright © 2002 Delmar Thomson Learning Octal Number System Place Values
Copyright © 2002 Delmar Thomson Learning Decimal, Hexadecimal, and BCD Comparisons
Copyright © 2002 Delmar Thomson Learning Place Values of Hexadecimal