Garbled communications with different style slave devices

Hello to everyone. I’m relatively new to the Digi community, especially in terms of installing and setting up a device from scratch. Let me give a breakdown of the equipment setup first.

I am using a Digi-IAP as the interface between multiple Modbus devices and my SCADA system. We are running Ignition version 7.7.5. The slave devices are being monitored only, they are not being used to control other devices.

Original configuration


6 Nuflo MCIII meters. Connected in series to Port 1. These devices have been functioning properly for over a year. Slave ID’s 1-6

1 Altronics DE-3000. This is connected to Port 2 via DB-9 and has been functioning properly for 6+ months. Slave ID 12

New Devices:

2 Murphy TTD’s, added in series to the end of the existing line. These are tied in to the Nuflo line in a junction panel so that everything was maintained in series.Slave ID 9-10

Here is my problem. From Ignition, I cannot poll both the Nuflo’s and Murphy TTD’s in a stable manner. I have had to set them up as two different devices within Ignition because the Murphy’s are ones based addressing and the Nuflos are not. I did this by using Ignition’s device manager to poll two different TCP ports on the Digi. My Nuflos are routed through port 504, the Murphys are routed through port 558. What I find is that no matter what, I can only poll one set of devices in a stable manner. If I disable the inputs from the Nuflos in Ignition, the Murphy’s will be completely stable. If I disable the Murphy’s, the Nuflos will be completly stable. If I enable them both, neither of them will function properly.

The DE-3000 I have coming in on Port 2 stays stable as long as I use the destination settings in the IA configuration page to only send the messages for slave ID 12 to that Port. Basically, it is completely isolated.

I have tried a lot of different things, and honestly a lot of it has turned into “What happens if I do this?” type games. I’ve reached the end of my knowledge level and I’m hoping someone can give me some insight. Any input is welcome. Thank you in advance.

I believe I had confused myself as to the purpose of using different TCP ports. By setting it up the way I had, I had made multiple masters, which really isn’t what I needed. I’ve changed the configuration so that all of the RS-485 devices are being routed through port 504. At this point, my Nuflo MCIII’s are stable, but my Murphy’s are not. This all may very well be an issue of my timing settings for the comms. I’m playing around with it now, trying to find something that makes a difference.