Tri-GP Communication Dropout with Local HMI and Honeywell PCDI

Hello All,

I’m trying to read/write to a triconex Tri-GP using a red lion local HMI and Honeywell DCS using PCDI via modbus. I have the triconex program as a slave, while the local HMI and DCS are masters.

Whichever application I power on first can read/write to the TRI-GP with no issues. For example, if the local HMI is initially on I have no issues, but when I power on the DCS, the DCS cannot communicate to the triconex, while the local HMI maintains communication. The same applies when using other modbus masters such as modscan.

I have an identical setup using Allen-Bradley controllers with a Prosoft card, and I have no issues read/writing from the DCS or local HMI.

Are there any unique issues or settings required to communicate from two masters to a single Tri-GP slave? All this is being done on a development system, so there is no danger in a process upset.


All help is much appreciated,

Hunter

More details:

I'm using an emulator for the Triconex Tri-GP. I've setup a virtual port for each of the masters within the Modbus configuration.

Does anyone know if the emulator can support multiple modbus TCP/IP masters?

Hello,

From the emulator help file:

Using Modbus TCP with the Emulator

If you are using Modbus TCP communication in your application, you can test it via the Emulator. However, the Emulator can use only one Modbus configuration. See Testing Modbus TCP Communication for more information.

Mark, many thanks for your response. I believe what that is referring to is the emulator can only emulate a single modbus configuration on a single network on a single COM module. For example, I have my configuration located on NET 1 on the left slot module.

However, I finally solved the problem. Each COM module can support up to 16 virtual ports. I had to change the TCP port number from the default 502 to 503, and make the same change on the second master.