MODBus TCP speed on slip ring

What are the details of your application? ModbusTCP is not specific to ctrlX. All slip rings are also different. There will be a degredating in the signal, due to the slip ring, which may impact the data throughput on that TCP segment. Higher quality slip rings will have less degredation and thus perform better for the network. It is a function of the slip ring design: quality of the materials used, size/bore diameter, etc.