Siemens SIMATIC S7 System Manual page 569

Example program status in an STL program
When you start program status in STL, the program editor window is divided into a code
region and a status region. You can customize the status region according to the types of
values that you want to monitor.
There are three categories of values that you can monitor in STL Status:
Operands
Logic stack
Instruction status bits
The STL Status tab of the Program Editor options (Page 571) in the Options settings of the
Tools menu ribbon strip allows you to select or deselect any of these categories of values. If
you deselect an item, it does not appear in the status display.
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
You can monitor up to 17 operands per instruction.
You can monitor up to the four most recent values from the logic
stack.
You can monitor up to eleven status bits.
Debugging and troubleshooting
10.2 Displaying program status
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