Program Edit In Run Mode - Siemens SIMATIC S7 System Manual

Programming concepts

5.8 Program edit in RUN mode

5.8 Program edit in RUN mode
Risks when downloading a program in RUN mode
When you download program changes to a PLC in RUN mode, your changes immediately
affect process operation. You have no margin for error; mistakes in your programming edits
can cause death or serious injury to personnel, and/or damage to equipment. Only qualified
personnel should perform a program edit in RUN mode.
Overview
The "program edit in RUN mode" feature allows you to make changes to a program and
download them to your PLC without switching to STOP mode.
● You can make minor changes to your current process without having to shut down.
Example: Change a parameter value.
● You can debug a program more quickly with this feature.
Example: Invert the logic for a normally open or normally closed switch.
If you download changes to a real process (as opposed to a simulated process, which you
might do in the course of debugging a program), be sure to think through the possible safety
consequences to machines and machine operators before you download.
You can download only the program block (OB1, subroutines, and interrupts) during a
program edit in RUN mode. You cannot download the system block or the data block during
a program edit in RUN mode.
Prerequisites for editing in RUN mode
You cannot download your program edits to a PLC that is in RUN mode unless you have met
these prerequisites:
● Your program must compile successfully.
● You must have successfully established communications between the computer where
you are running STEP 7-Micro/WIN SMART and the PLC.
● The firmware of the target PLC must support the program edit in RUN mode feature. Only
S7-200 SMART CPUs with version V2.0 or later firmware support the program edit in
RUN mode feature.
● You must provide a password for a protected POU to open the block (for normal editing,
edit in RUN mode, and program status operations).
If you change the PLC to STOP mode while a program edit in RUN mode is in progress, the
PLC aborts the editing session.
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WARNING
System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART