Siemens SIMATIC S7-200 System Manual page 259

Hardware Troubleshooting Guide and Software Debugging Tools
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.
Downloading the Program in RUN Mode
RUN-mode editing allows you to download only your program block while the S7-200 is in RUN
mode. Before downloading the program block in RUN mode, consider the effect of a RUN-mode
modification on the operation of the S7-200 for the following situations:
If you deleted the control logic for an output, the S7-200 maintains the last state of the
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output until the next power cycle or transition to STOP mode.
If you deleted a high-speed counter or pulse output functions which were running, the
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high-speed counter or pulse output continues to run until the next power cycle or transition
to STOP mode.
If you deleted an Attach Interrupt instruction but did not delete the interrupt routine, the
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S7-200 continues to execute the interrupt routine until a power cycle or a transition to STOP
mode. Likewise, if you deleted a Detach Interrupt instruction, the interrupts are not shut
down until the next power cycle or transition to STOP mode.
If you added an Attach Interrupt instruction that is conditional on the first scan bit, the event
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is not activated until the next power cycle or STOP-to-RUN mode transition.
If you deleted an Enable Interrupt instruction, the interrupts continue to operate until the
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next power cycle or transition from RUN to STOP mode.
If you modified the table address of a receive box and the receive box is active at the time
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that the S7-200 switches from the old program to the modified program, the S7-200
continues to write the data received to the old table address. Network Read and Network
Write instructions function in the same manner.
Any logic that is conditional on the state of the first scan bit will not be executed until the
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next power cycle or transition from STOP to RUN mode. The first scan bit is set only by the
transition to RUN mode and is not affected by a RUN-mode edit.
Tip
Before you can download your program in RUN mode, the S7-200 must support RUN mode
edits, the program must compile with no errors, and the communications between
STEP 7--Micro/WIN and the S7-200 must be error-free.
You can download only the program block.
To download your program in RUN mode, click on the Download button or select the File >
Download menu command. If the program compiles successfully, STEP 7--Micro/WIN downloads
the program block to the S7-200.
Exiting RUN-Mode Edit
To exit RUN-mode editing, select the Debug > Program Edit in RUN menu command and
deselect the checkmark. If you have changes that have not been saved, STEP 7--Micro/WIN
prompts you either to continue editing, to download changes and exit RUN-mode editing, or to exit
without downloading.
Chapter 8
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