Program; 1Classifications Of Program; Program Execution Procedure - LG MASTER-K 120S Series User Manual

Chapter 5 Power Supply / CPU

5.4 Program

5.4.1 Classifications of Program
All functional elements need to execute a certain control process are called as a 'program'. In MASTER-K120 series, a
program is stored in the EEPROM mounted on a CPU module or flash memory of a external memory module. The following
table shows the classification of the program.
Program type
Scan program
Time-driven interrupt
program (TDI)
Process driven interrupt
program (PDI)
High speed counter driven
interrupt program(HSCDI)
Subroutine program

5.4.2 Program Execution Procedure

The following diagram shows that how the CPU module process programs when the CPU module is powered on or switched to
RUN mode.
Start processing
Scan program
END processing
The scan program is executed regularly in every scan
The TDI programs are executed with a constant time interval specified with parameter setting.
The PDI programs are executed when external interrupt input is applied and the corresponding
interrupt routine is enabled by EI instruction.
This interrupt programs are executed when comparison task signal is applied.
(Standard Type only)
The subroutine programs are executed when they are called by the scan program with a CALL
instruction.
5-14
Description
Subroutine program
PDI program
TDI program
HSCDI program