Siemens CPU 31 Series - Page 92

Cycle and reaction times
5.2 Cycle time
CPU 31xC and CPU 31x, Technical Data
5-6 Manual, 01/2006 Edition, A5E00105475-06
Operating system processing time at the scan cycle check point
The table below shows the operating system processing time at the scan cycle checkpoint of
the CPUs. These times are calculated without taking into consideration times for:
• Testing and commissioning routines, e.g. status/controlling of variables or block status
functions
• Transfer and deletion of blocks, compressing user program memory
• Communication
• Writing, reading of the SIMATIC Micro Memory Card with SFC 82 to 84
Table 5-6 Operating system processing time at the scan cycle check point
CPU Cycle control at the scan cycle check point (CCP)
312C 500 μs
313C 500 μs
313C-2 500 μs
314C-2 500 μs
312 500 μs
314 500 μs
315 500 μs
317 150 μs
319 77 μs
Extension of the cycle time as a result of nested interrupts
Enabled interrupts also extend cycle time. Details are found in the table below.
Table 5-7 Extended cycle time due to nested interrupts
Interrupt type Process
interrupt
Diagnostic
Interrupt
Time-of-day
interrupt
Delay interrupt Watchdog
interrupt
312C 700 μs 700 μs 600 μs 400 μs 250 μs
313C 500 μs 600 μs 400 μs 300 μs 150 μs
313C-2 500 μs 600 μs 400 μs 300 μs 150 μs
314C-2 500 μs 600 μs 400 μs 300 μs 150 μs
312 700 μs 700 μs 600 μs 400 μs 250 μs
314 500 μs 600 μs 400 μs 300 μs 150 μs
315 500 μs 600 μs 400 μs 300 μs 150 μs
317 190 μs 240 μs 200 μs 150 μs 90 μs
319 72 μs 87 μs 39 μs 26 μs 10 μs
The program runtime at interrupt level must be added to this time extension.