Ethernet - SLC 5/05 vs ML1400

[Lobstah1 0]

We are setting up a wireless (narrow band) Ethernet network with a SLC 5/05 PLC as the master that uses MSG blocks to read and write into remote PLCs. The remote sites with SLC's have a better time with the MSG's than sites with ML1400's. If you watch the PLC ladder where the MSG block are going to ML1400 site, it seems like there is a pause (2 to 3 sec) where the master is auto-negotiating the link with the ML1400. For the SLC sites, there is little or no pause. I did some research and it appears the SLC 5/05 was developed to use the CSP/PCCC protocol but later versions were developed to also be compatible with the EIP/PCCC protocol. Is there something that can be done to eliminate the "pause"? The MSG blocks for the ML1400 already have the multi-hop option turned on.

We are considering a test where we change the master PLC to a ML1400. Would the ML1400 PLC have a similar problem communicating with a SLC 5/05?

Another option would be splitting the master PLC duties by having two master PLCs, one a SLC and the other ML.

Rockwell Automation has not been much help with this problem.