Features For Debugging Your Program - Siemens Simatic S7-200 System Manual

S7-200 Programmable Controller System Manual

Features for Debugging Your Program

STEP 7–Micro/WIN provides several features to help you debug your program: bookmarks, cross
reference tables, and run-time edits.
Using Bookmarks for Easy Program Access
You can set bookmarks in your program to make it easy to move back and forth between designated
(bookmarked) lines of a long program. You can move to the next or the previous bookmarked line of your
program.
Using the Cross Reference Table to Check Your Program References
The cross reference table allows you to display the cross references and element usage information for
your program.
Cross
The cross reference table identifies all operands
Reference
used in the program, and identifies the program
block, network or line location, and instruction
context of the operand each time it is used.
You can toggle between symbolic and absolute
view to change the representation of all
operands.
8
Tip
Double-clicking on an element in the cross reference table takes you to that part of your program or
block.
Editing Your Program in RUN Mode
CPU 224 Rel. 1.10 (and higher) and CPU 226 Rel. 1.00 (and higher) models support RUN mode edits.
The RUN mode edit capability is intended to allow you to make small changes to a user program with
minimal disturbance to the process being controlled by the program. However, implementing this capability
also allows massive program changes that could be disruptive or even dangerous.
Warning
When you download changes to an S7-200 in RUN mode, the changes immediately affect process
operation. Changing the program in RUN mode can result in unexpected system operation, which could
cause death or serious injury to personnel, and/or damage to equipment.
Only authorized personnel who understand the effects of RUN mode edits on system operation should
perform a RUN mode edit.
To perform a program edit in RUN mode, the online S7-200 CPU must support RUN mode edits and must
be in RUN mode.
1. Select the Debug > Program Edit in RUN menu command.
2. If the project is different than the program in the S7-200, you are prompted to save it. The RUN
mode edit can be performed only on the program in the S7-200.
3. STEP 7–Micro/WIN alerts you about editing your program in RUN mode and prompts you to either
continue or to cancel the operation. If you click Continue, STEP 7–Micro/WIN uploads the program
from the S7-200. You can now edit your program in RUN mode. No restrictions on edits are
enforced.
Tip
Positive (EU) and Negative (ED) transition instructions are shown with an operand. To view information
about edge instructions, select the Cross Reference icon in the View. The Edge Usage tab lists numbers
for the edge instructions in your program. Be careful not to assign duplicate edge numbers as you edit
your program.
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Figure 8-1 Cross Reference Table