PLC Programming

PLC Programming

1. Number Systems

   • Decimal
     • Base 10
     • Used in everyday life
     • Not used by computers
   • Binary
     • Based on base 2
       • Weights are powers of two
       • 2 digits only
     • Bit: 1 binary digit
       • Byte: 8 bits
         • Word: 2 Bytes
       • HIGH or LOW
   • Hexadecimal
     • Base 16
       • 16 digits

2. Programming systems

   • Ladder Logic
     • Uses components resembling hard wired diagrams
   • Statement List
     • Operations Represented in plain text
   • Function Block Diagram
     • Use rectangles with logic functions

3. PLC Scan

   • Repetitive process that performs the PLC program
   • Reads Inputs
   • Executes Program
   • Runs Diagnostics
   • Performs Communications
   • Updates Inputs