Receiving Modbus into S7-1500

We have an old modicon bit of kit that receives 48 registers (24 reals) from a PC system via modbus TCP. We're looking to upgrade the PLC to S7-1500 but I'm not exactly sure how to get those registers into the S7. The PC system is simply sending these values to registers starting 405200 at the specified IP address (also repeating this for a second identical machine with different IP)

We don't have access to change the PC side of things so if anyone can point me in the right direction with the right instruction to use, I'm thinking I need maybe TRCV?

The S7-1500 can be both Modbus TCP client and server.
Maybe this useful despite that it is for an S7-1500 with an S7-1200 instead of an S7-1500 with an external Modbus TCP partner:
https://support.industry.siemens.com/cs/fr/en/view/102020340

I had a play around on Friday with this but can't seem to get a connection to either MB block though I'm not sure they are the right blocks anyway.

In the existing setup I think the PC system is the master and the registers are written to the specified PLC registers and has no config in the PLC that the PC system even exists. I need to replicate this setup in the new S7 so that it just accepts some values from an IP address without needing something setup on the other end.

I'm unable to try anything else at the minute as the line is running again but if anyone else has any pointers in the meantime I'm all ears.

ON 1200 and 1500 you have for modbus TCP MB_server and MB client blocks.


You need now MB_server.


From manual and starting around page 949.

https://support.industry.siemens.com/cs/il/en/view/107623221

You need to offset your MB serer to start from address 5200 (or 4501) I think.


Other parameters needed is at least connection ID, port (usually 502).


If yo have several different areas, then you need change ports to 502, 503, 504.
If you have only holding registers on same area then you can use 502 for all. (you can have only one DB-area / port / block)