Siemens SIMATIC S7-1500 System Manual page 346

Test and service functions
14.1 Test functions
Testing with breakpoints provides you with the following advantages:
• Localization of logic errors step by step
• Simple and quick analysis of complex programs prior to actual commissioning
• Recording of current values within individual executed loops
• Using breakpoints for program validation is also possible in SCL or STL networks within
LAD/FBD blocks.
NOTE
Restrictions during testing with breakpoints
• If you test with breakpoints, there is a risk that you will exceed the cycle time of the R/H-
CPU.
• SYNCUP is rejected if a breakpoint is set in the RUN-Solo system state.
• If you set breakpoints in the standard user program in an HF-system with the CPUs
1518HF-4 PN, errors occur in the safety program. If you nevertheless want to use
breakpoints for testing, you must disable safety mode beforehand. Observe the additional
information about the errors and effects in the programming and operating manual
SIMATIC Safety - Configuring and Programming
(https://support.industry.siemens.com/cs/ww/de/view/54110126).
Difference between modifying and forcing
The fundamental difference between the modifying and forcing functions is the storage
behavior:
• Modifying: Modifying tags is an online function and is not stored in the CPU. You can end
the modifying of tags in the watch table or force table or by terminating the online
connection.
• Forcing: A force job is written to the SIMATI​ ​ C memory card and is retained after a POWER
OFF. The S7‑1500R/H CPU displays an active force job with a symbol. You can only end the
forcing of peripheral inputs and peripheral outputs in the force table.
A force job is transferred to the backup CPU in SYNCUP. The force job is then effective in
both CPUs in the RUN-Redundant system state.
Testing with watch tables
The following functions are available in the watch table:
• Monitoring of tags
Using watch tables, you can monitor the actual values of the individual tags of a CPU user
program.
– On the PG/PC
– On the display of the CPU
Please note the following requirement for displaying the tag values on the CPU display:
You must specify a symbolic name for each tag in the "Name" column of the force table.
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S7-1500R/H redundant system
System Manual, 11/2022, A5E41814787-AD