kupmic

Have same issue, where is the problem?
No possible to solve it.

You do not give the forum volunteers anything to work with. The PLC going to stop can be caused by several conditions. Only one of the many reasons has to do with the program and block size. 

The free memory on the PLC should be big enough for the change version of the block to be loaded. Only thereafter is the 'old' version removed from memory.

The firmware version of the CPU plays a role in how the memory is managed. Firmware V4.2 and V4.6 (S7-1200) saw enough of a method change so that more memory is made available to the user program. Therefore mention:
1. The firmware version of the PLC hardware. (Assuming S7-1200 -- right?)
2. The firmware version mentioned in the project (which could be lower).
3. The size of the block that causes the STOP.
4. The type block which causes the stop (Adding an OB will cause issues.)
5, The size of the program & size of the free space.
6. The method used to download the program. (Highlighting the PLC hardware icon while requesting download, may cause problems.)
7. The version of the software used. (Step7 V10,5 will stop the PLC)
8. The win numbers for the next Euro Millions Lottery. 

Update to the very latest firmware for the s7-1200.  I believe the last couple of firmware updates enabled something like an extra 25KB of working memory for free.

That might be enough.

I have a similar situation in many of my projects.  I have one DB used in in many OBs and calls to FBs/FCs.  Updating that DB generates too many OB/FB/FC changes to allow the PLC to keep running.

There's a horrible work-around - for processes that need to run 24x7.  If you are in that situation, please look through these forums for a solution - I posted one solution, and others may have provided a slightly different solution that suits your needs better.

Involves creating a 2nd DB - a copy of the existing one that always causes me to have a PLC stop when updating.  Modify the new DB and then replace all references to the OLD DB & tag with the new DB & tag.  Using cross references makes this go very quickly.  Then you can try downloading those changes.  If it does not work, you can adjust things until it does.

viper_lasser

I have project with two the same plc S7-1214 DC/DC/DC.

In first plc when I change my DB (add/rename 1 row - word) then Tia during downloading project to plc want to stop plc.

Tia show "Number of blocks is to high to load in run. Set the CPU to stop to load the blocks.

In second plc project is little smaller and I can change some FB/DB's without stoping plc during downloading project to plc.

In both plc firmware is 4.2.x

How can I do the same in first plc ?