When searching the web it is not completely clear what will put the plc in stop mode when downloading. It would be really helpful to have some good info, best of all a video, about this.
From siemens:
"Considerations when downloading in RUN mode
Before downloading the program in RUN mode, consider the effect of a RUN-mode modification on the operation of the CPU for the following situations:
If you deleted the control logic for an output, the CPU maintains the last state of the 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 high-speed counter or pulse output continues to run until the next power cycle or transition to STOP mode.
Any logic that is conditional on the state of the first scan bit will not be executed until the 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 download in RUN mode.
The current values of data blocks (DB) and/or tags can be overwritten.Note Before you can download your program in RUN mode, the CPU must support changes in RUN mode, the program must compile with no errors, and the communication between STEPÂ 7, and the CPU must be error-free. You can make the following changes in program blocks and tags and download them in RUN mode:
- Create, overwrite, and delete Functions (FC), Function Blocks (FB), and Tag tables.
- Create and delete Data Blocks (DB); however, DB structure changes cannot be overwritten. Initial DB values can be overwritten. You cannot download a web server DB (control or fragment) in RUN mode.
- Overwrite Organization Blocks (OB); however, you cannot create or delete OBs.
You can download a maximum number of twenty blocks in RUN mode at one time. If you must download more than twenty blocks, you must place the CPU in STOP mode. Once you initiate a download, you cannot perform other tasks in STEPÂ 7 until the download completes."