Chapter 2 Devices Table of Contents 2.1 Introduction to Devices ......................................................................... 2-2 2.1.1 Device Table ................................................................................. 2-2 2.1.2 Basic Structure of I/O Storage ......................................................... 2-3 2.1.3 Relation Between the PLC Action and the Device Type ........................ 2-3 2.1.4 Latched Areas in the Device Range .................................................. 2-4 2.2. Device Functions ..................................................................................
2-5 2.2.1 Values and Constants ..................................................................... 2-5 2.2.2 Floating-point Numbers .................................................................. 2-7 2.2.2.2 Decimal Floating-point Numbers ..................................................... 2-8 2.2.3 Strings ......................................................................................... 2-8 2.2.4 Input Relays (X) ........................................................................... 2-10 2.2.5 Output Relays (Y) .........................................................................
2-10 2.2.6 Auxiliary Relays (M) ...................................................................... 2-11 2.2.7 Special Auxiliary Relays (SM) ......................................................... 2-11 2.2.8 Refresh Time for Special Auxiliary Relays ......................................... 2-37 2.2.9 Stepping Relays (S) ...................................................................... 2-45 2.2.10 Timers (T) ................................................................................... 2-45 2.2.11 Counters ......................................................................................
2-47 2.2.12 32-bit Counters (HC) ..................................................................... 2-48 2.2.13 Data Registers (D) ........................................................................ 2-50 2.2.14 Special Data Registers (SR) ........................................................... 2-50 2.2.15 Special Data Registers Refresh Conditions ........................................ 2-77 2.2.16 Additional Remarks on Special Auxiliary Relays and Special Data Registers……………………………………………………………………………………………….….2-79 2.2.17 Index Register (E) ........................................................................
2-95 2.2.18 File Registers (FR) ........................................................................ 2-95 2.2.2.1 Single-precision Floating-point Numbers .......................................... 2-7 2-1 2