i i i4.6.4 Setting a Real-time Clock ............................................................. 4-46Chapter 5 Understanding Common Devices5.1. Introduction ................................................................................... 5-25.2. Common Devices ............................................................................ 5-25.2.1. Functions of Common Devices......................................................... 5-25.2.2. Device List ................................................................................... 5-25.2.3. Latched Devices ............................................................................ 5-45.2.4. Input Relays (X) ........................................................................... 5-55.2.5. Output Relays (Y) ......................................................................... 5-55.2.6. Auxiliary Relays (M) ...................................................................... 5-65.2.7. Special Auxiliary Relays (SM/AM) .................................................... 5-65.2.8. Data Registers (D) ........................................................................ 5-65.2.9. Special Data Registers (SR/AR) ....................................................... 5-75.2.10. Link Registers (L) .......................................................................... 5-75.2.11. Stepping Relays (S) ....................................................................... 5-75.2.12. Timers (T).................................................................................... 5-75.2.13. Counters (C) ................................................................................ 5-95.2.14. 32-bit Counters (HC/AC) .............................................................. 5-105.2.15. Index Registers (E) ..................................................................... 5-105.2.16. Values and Constants (K, 16#) ..................................................... 5-115.2.17. Floating-point Numbers (F, DF) ..................................................... 5-125.2.18. Strings (“$”) ............................................................................... 5-145.3. EtherCAT Symbols ........................................................................ 5-165.4. Symbols ........................................................................................ 5-165.4.1 Application of Symbols ................................................................. 5-165.4.2 Classes ...................................................................................... 5-165.4.3 Data Types................................................................................. 5-175.4.4 Using Devices, Symbols and Instructions ........................................ 5-185.4.5 Modifying a Symbol with an Index Register ..................................... 5-195.5. User-defined Data Type (ENUM) ................................................... 5-20Chapter 6 Understanding Motion Control Devices6.1 Motion Control Devices ................................................................... 6-2