Chapter 6 Applied Instructions Step 2: edit the register to set up the reference values, and the observational error when entering and leaving. Step 3: set up the initial values and write the programs. 6_ 6-225 Device D D500 D502 D504 Reference value for comparison (32-bit) K2000 K3000 K4000 Device D D506 D508 D510 Observational error when entering (32-bit) K100 K120 K130 Device D D512 D514 D516 Observational error when leaving (32-bit) K50 K-20 K20 Device D D2000 D2001 D2002 Value of the head index (16-bit) K0 K0 K0 Device D D2003 D2004 D2005 Value of the tail index (16-bit) K0 K0 K0