ModbusTCP Citect

[IngPianetti]

Hi everybody!

I'm working with Citect 2016 (update 38).

We need to establish a Modbus TCP communication with a PLC in plant. Nevertheless, the SCADA never gets to communicate to this PLC. After running many tests, we found out that the SCADA never sends any kind of request to the mentioned PLC (we used wireshark). In order to rule out any kind network problem, we run a ModbusTCP Server in a PC which was at reach of the SCADA, but the results were the same. After that we proceed to create an empty new project pointing just to the same testing ModbusTCP Server. But to our surprise, it worked perfectly well, even though the parameters (port, protocol, device, variable addresses) were the same as the ones in our original project.

It is the first time something like this happend to us. We have many Schneider M340 using ModbusTCP without any kind of problems.

Any ideas?? Thanks in advance

[AdamWoodland]

Hi,

This section of the Community website is for the ClearSCADA / GeoSCADA product. For CitectSCADA / Plant SCADA product discussions try https://community.exchange.se.com/t5/Industry-Automation-and-Control/bd-p/industry-automation-contro...

Someone here might know, but you'll have more success at the Automation and Control section.

[S_Stolyarov]

Am  I right that the new project in SCADA works well with Modbus TCP server?

[IngPianetti]

Yes, you're totally right. 

The new project has only one device, which is the pc running the testing ModbusTCP server. With this simple configuration, the project is able to reach the test pc.

On the other hand, when the parameters of the pc are loaded to the original project, citect doesn't even send a modbus tcp frame to request data to this device, even when the parameters (device, port, protocol) are the same.

We're completely lost because we have many Schneider M340 running in plant with ModbusTCP without any issues.

[IngPianetti]

Thank you very much for your piece of advice. I'm new to this forum so, any help is well appreciated.

[S_Stolyarov]

It is a very-very weird situation. Maybe you have somewhere doubled device with the same IP address in your original program?

[kingslim]

.... i have addressed that in https://community.exchange.se.com/t5/Industry-Automation-and-Control/Citect-2016-ModbusTCP-communica...  

Did it work ? 

[IngPianetti]

Hi! 

It's a good guess. But it's not the case either. We run a a ModbusTCP client to simulate the SCADA on a computer to poll the remote device(PLC). The PLC always sent a response back. We did this first to make sure the PLC was working well but at the same time we checked the network