Max Size of a byte Buffer[]

[Jody Arigi]

Hi,
i want to know what is the max size of a DB in PLC that can be read into a buffer of byte (byte Buffer[] ) using ReadArea(). I use ReadArea() to read a whole DB at once. Does the buffer of byte itself has a maximum space?

any response is very much appreciated! Thank you!

Jody

[Davide Nardella]

The buffer has no maximum size, but a DB into the PLC can be max 32K (S7300) or 64K (S7400).
You can always transfer the whole DB in a single operation.

[Jody Arigi]

Hi Dave thanks for the answer,

1. how big can an S7 1500 have in a single DB to be read? Did you mean 32 and 64 KByte above
2. what is actually a PDU size? what does it have to do with the buffer size or DB size?
   i appreciate your response very much! thanks once again.

Edit: i read on SIEMENS website that a DB in S7 1500 can have up to 5 MByte of datas, if i had that many in my DB can i read all of them in a single ReadArea and save it in one Buffer of byte? Thanks