Dear friends,

I have the following setup:
1 main PLC: 6ES7 510-1DK03-0AB0
28 S7-1200 PLCs: 6ES7 214-1BG40-0XB0
The 1DK03 main PLC will send and receive data from the other 28 PLCs.

I prefer not to use PUT-GET communication due to disconnections and security issues. When I use SYNC-RCV_C, I can only communicate with a maximum of 16 devices (it seems there is a limit based on my research). When using I-Device, the datasheet mentions 32 devices, but I can only add up to 4 controllers.

The DB load is not very high, with an offset of 9.0. I need your help.

I considered using OPC-UA, but it is not available in the S7-1200. All PLCs are on the same PROFINET network. I thought of creating two separate PROFINET networks and making the SCADA computer dual Ethernet to use 16-16 SYNC-RCV. However, I am concerned that I might be doing the methods mentioned above incorrectly, so I wanted to ask knowledgeable professionals about it.
I did not create the configuration. Unfortunately, I am unable to create a new configuration.

I look forward to your recommendations. Thank you in advance for your valuable insights.