S2 profinet IRT extra bytes

Hi, I am working on an application for Profinet IRT using S2.

We are struggling a bit to understand the sizes. Maybe you can help :slight_smile:

We are configuring 3 ADIs in write and 10 ADIs in read. the Mapped PD sizes are:

write: (mapped WrPd 328)
read: (mapped RdPd 1084)

In the PCS7 project importing GSDML file, we get additional 19 bytes extra for each direction. I cant find the reason for this in the Anybus documentation.

Do anyone have an explanation?


Hello Rislaa,

Do you have remapping enabled? You may be changing the default mapping when mapping data to the PLC.
Where are you getting the mapped size from? Where are you seeing the 19 extra bytes in.

Hello Deryck,

Some progress have been done since the post. It seems like the sizes of the ADIs on the PLC size is correct. However, there are 19 extra bytes in the input and output buffers of the S2 on the PLC side.

Maybe these are some extra bytes related to S2 functionality that is added on the PLC side?

I am sorry the question is so vague… We have been able to reduce the total mapping size as well so this is no real issue, I just want to try to understand where they come from :slight_smile:



This is what I was thinking, it may be data related to the PLC. I am still not sure exactly where you are seeing the extra bytes.

Sorry, here is where the extra bytes are shown:

It is a popup from PCS7. Refer to the first post for our mapped sizes.


I would double check what objects are mapped in the configuration and make sure they match the ADI you are looking to map. If you have remapping enabled you may be changing the default mapping with the data configured in the PLC setup.

Thank you for the suggenstion. I will check!