Calculating The F-Cycle Monitoring Time (For Block F_Cyc_Co) - Siemens SIMATIC PCS 7 Operating Manual

Configuring the safety program
7.11 Monitoring times and system response times
7.11.2

Calculating the F-cycle monitoring time (for block F_CYC_CO)

The F-CPU runs execution time monitoring for every cyclic interrupt OB (OB 30 - OB 38)
containing F-runtime groups.
Procedure
The first time the F-program is compiled, you will be prompted to enter a value for the
maximum cycle time (MAX_CYC) which may elapse between two calls to this cyclic interrupt
OB. The default for the maximum F-cycle time is 3000 ms.
Should this default value not be suitable for your process, you can modify it directly at the
F_CYC_CO block (located in the automatically generated @F_CycCo-OB3x chart).
You will need the following parameters for an exact calculation of the scan cycle monitoring
time for a cyclic interrupt OB:
T
CI
T
P15
Special
handling
T
Prog
T
CiR
T
CiRmax
T
CImax
Extract from the "s7ftimea.xlsm" Excel file:
136
Configured execution time of the cyclic interrupt OB in which the F_CYC_CO F-function
block is called.
Configured "max. disabling time for priority classes > 15"
Only relevant for redundant systems. Enter a 0 if you are not using an FH system.
If the OB is entered as a cyclic interrupt OB with special handling, set "Yes" here.
Program runtime of the cyclic interrupt OB
CiR synchronization time
Upper limit of the CiR synchronization time (default setting: 1 s)
Shortest possible time for scan cycle monitoring of the cyclic interrupt OB
Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB