trouble with AB 1747-AIC

I use DH485 network using the AB 1747-AIC and 1761-Net AIC as attached, But there is a problem in one of the AB 1747-AIC that often gets lost, the problem occurs in the fifth node so that the Panel Viewing 900 sixth node cannot communicate with the fifth node SLC 500/03. Please help with this problem

DH485 is sensitive to the number of nodes and the amount of data that is being sent from node to node.

Did something change recently to cause this problem to appear? For example, did you add a node, or increase the amount of data in one of the HMI units?

What node number is the 1747-UIC? Does having the UIC connected affect the frequency of the problem?

Do any of the HMI units communicate with multiple nodes on the network?

To figure out what is going on, it may be useful to read this application guide and apply the information to your particular set up:

DH-485 Network Throughput Timing

Paul