Siemens SIMATIC PCS 7 Configuration Manual page 91

Checking the local data requirement
Use the CFC editor to compare the local data requirement and amount in the CPU. Use the
"Options > Chart > Chart Reference Data" command to open the editor in which the "Local
Data" can be viewed. An OB configured too low is shown in red in this view.
The maximum amount of local data depends on the CPU; for example, it is 65536 for CPU
410-5HX08-0AB0 (V8.1).
Communication resources
The CPU also determines the maximum number of possible communication jobs.
A CPU 410-5H can, for example, manage a maximum of 10,000 communication jobs. Block
instances from BSEND, BRCV, ALARM, ALARM_8, ALARM_8P, NOTIFY, and AR_SEND, for
example, always need one communication job.
A process object or its function block (FB) usually requires up to 3 communication jobs in each
instance.
With this CPU the default setting is for 10000 communication jobs which is adequate for typical
quantities of block instances. A check is made when compiling the charts during the
engineering phase as to whether a warning threshold has been crossed (with a default setting
of 90%).
Note
Adjust the warning level according to the planned number of PO for a CPU. Set the warning
level of 2,500 communication jobs (factor 2.5) taking the example of the CPU 410-5H with
System Expansion Card 1000 PO. Select the chart folder of the automation system to
determine the currently used communication jobs. Via "Extras > Charts > Chart reference
data", you can open the relevant program where you will find the "Statistics" view with the
number of communication jobs.
Compendium Part A - Configuration Guidelines (V8.2)
Configuration Manual, 08/2016, A5E38166869-AA
Configuration of the hardware (AS and I/O)
6.1 General CPU settings (H system and standard AS)
91