363
SECTION 6
Program Execution Timing
The timing of various operations must be considered both when writing and debugging a program. The time required to
execute the program and perform other CPU Unit operations is important, as is the timing of each signal coming into and
leaving the PC in order to achieve the desired control action at the right time. This section explains the cycle and shows how to
calculate the cycle time and I/O response times.
6-1 Cycle Time 364. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2 Calculating Cycle Time 368. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2-1 PC with I/O Units Only 369. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2-2 PC with Host Link and Remote I/O Master Units 369. . . . . . . . . . . . . . . . . . . . . . . . .
6-3 Instruction Execution Times 371. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4 I/O Response Time 380. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-1 Basic Systems 380. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-2 Remote I/O Systems 381. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-3 Host Link Systems 384. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-4 PC Link Systems 384. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-5 One-to-one Link I/O Response Time 387. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-6 Interrupt Response Times 389. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .