Computer Hardware User Manual

359
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 360. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2 Calculating Cycle Time 364. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2-1 PC with I/O Units Only 365. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2-2 PC with Host Link and Remote I/O Master Units 365. . . . . . . . . . . . . . . . . . . . . . . .
6-3 Instruction Execution Times 367. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4 I/O Response Time 376. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-1 Basic Systems 376. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-2 Remote I/O Systems 377. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-3 Host Link Systems 380. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-4 PC Link Systems 380. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-5 One-to-one Link I/O Response Time 383. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4-6 Interrupt Response Times 385. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .