Unknown device tags

[GVG]

Hi everybody,

I want to connect rapid Scada to an AB CompactLogix L33ER. This PLC is already connected to a local HMI where the user can visualize some temperature and pressure values, so I just want to pass those values to rapid Scada. The problem is that someone else programmed the PLC and I have no access to its configuration, so I have no clues about the PLC’s tags, I just have the IP address. ¿Does anybody have an idea of how to obtain the existing tags so I can create a correct device template?

I would be very please if someone can help me.
Cheers!

[Mikhail]

Hi,

Do you know at least a communication protocol? Is it Modbus TCP or other one?

[manjey73]

There is a similar task, but AB Micrologix is used, according to the description PLC data support Modbus, but it is used or not unknown. You must put the port watcher on the exchange between the PLC and the HMI panel to read the traffic between them. But not the fact that it will help. Plus, try to connect to the PLC with Modbus scanners.
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[GVG]

Hi,
I read the traffic between them, just found some messages in TCP protocol. I’ll try as you are suggesting with a Modbus scanner.

[manjey73]

You can check if this applies to Modbus using this link
Rapid SCADA Modbus Parser
However, you need to find the right start and end of the parcel in the TCP scanner

[Mikhail]

Also try WireShark

[Mikhail]

You should try poll any addresses using Rapid SCADA. Some devices answer ILLEGAL ADDRESS, but others return correct response filling with zeros. If yours of the second type, you can find non zero registers.

[GVG]

Hi,
As you suggested, I used wireshark to read the parcels… At the end it was not TCP protocol so I will try to configure an OPC.
A Panel View is already connected to the system, so I imagine that an OPC server should have been installed somewhere in. Even so I will need to install a new OPC Server on my PC to communicate to the PLC. Am I right?

[manjey73]

Could you share the wireshark logs that you received by scanning the packets ? If anything, there is the Allen Bradley Protocol.

[Mikhail]

Is it possible that a proper OPC is already installed?

[GVG]

The only package I see in Wireshark is in ARP protocol, to identify the PLC, nothing more. I thought I was receiving TCP packages but actually no, it was me forcing the communicator to talk in modbus TCP.
I configured the OPC with Matrikonopc and now I have acces to the PLC tags but got an error while adding tag:

Error check tag type:
Receiving data from OPC server failed.
Add the tag manually by specifying its type

[Mikhail]

Error check tag type:
Receiving data from OPC server failed.
Add the tag manually by specifying its type

Please provide a screenshot.

[GVG]

https://www.dropbox.com/s/9ppmzbktcvgtiw0/Captura1.JPG?dl=0
https://www.dropbox.com/s/7s6g3uivxs1in08/Captura2.JPG?dl=0

I click on the add button, but not able to write in the Name field, nor in Path field. I´m able to add items from other folders though.

[Mikhail]

Thank you.
Could you check if the problem also occurs in case of using Matrikon OPC Simulation Server?

Despite of the error, a name should be set non empty. Are there tags that can be added with non empty name? What if you save settings and restart the Communicator service?

[GVG]

OPC Simulation is working well, actually I don´t have the option to add items manually, neither to modify the names. I tried restarting communicator and also setting the tag´s names from administrator but still not work. Is it possible that this tags are blocked to use them outside OPC server?

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