Tools to Monitor Traffic on a DH-485 Network

We are trying to optimize the traffic on a congested DH-485 network. What tools are available for monitoring traffic on a DH-485 network? I would be happy with something that could display a simple count of messages/errors to and from each node on the network.

This should do what you want http://www.fte.com/products/NetDecoder-18.asp

NetDecoder is the main battle tank of my communications troubleshooting toolkit. It is the only passive DH-485 analyzer that I know about, and FTE just rolled out two new USB/serial (one RS232, one RS422/485) interfaces.

If you do network troubleshooting extensively (it's a major part of my business), FTE is well worth the investment. It has solved problems for me that no other tool could.

The first thing I would do is make sure that every device in my network had a Channel Diagnostic file defined for the DH-485 network port. This is a great way to get the baseline information about how much traffic and how many errors are being seen by each device on the network. RSLinx should also give you some Station Diagnostic counter values for each device when you right-click in the RSWho view.

If you have the opportunity to get an oscilloscope onto the Data A and Data B signals of the network (relative to the isolated Common wire) that may help you get an idea of the signal quality.