Johannes Alef

I have a C# program that calls Snap7 via DLLImport to Upload entire blocks from a Type 300 PLC. Some of the DBs are rather large. One of them for example has a loadsize of 91666 bytes. The data is only 26164 bytes but with header and data for a user defined datatype that is used the block gets this large. When I try to upload this block, my program just crashes and in the windows event log I find an error that usually indicates heap corruption (exceptioncode 0xc0000374). Exception Handling in C#...

Okay, thanks for the info.

In the Connect funtion, a TCP ping is tested before the actual connection is established. What exactly is the purpose of this ping? My guess is that it just a shortcut to check if a connection is possible at all. Snap7 does not seem to do this and works fine, but I want to make sure that there is not something I am not seeing. This ping sometimes creates a problem for us, when connecting to a plc that can only handle a limited amount of connections. Because sometimes it seems that the ping connection...