Two issues with AB7570



I am setting up a Profinet to OPC UA gateway. By now I have two main questions:

  1. I can see the exported variables with UaExpert. But I cannot see them with another client as OPC UA Client. I have not tried other clients. Is it normal? Shouldn’t any client see the variables?
  2. I am exporting an UINT variable from an S7-1200 PLC, and I am defining a UINT16 tag with the config program, But it seems the “endian” is different (I receive the two bytes swapped). I cannot find any way to configure the endianness. Should I invert the bytes in my code? I hope not…

Thank you in advance!


Hi @joseluisb,

For #1 I would need to know more information. You should be able to see the variables with any OPC UA Client that was properly configured.

For #2, can you provide the serial number for the gateway? There was an issue with this a few years ago with the Profinet device, but I believe it was resolved in the firmware. The gateway should not be changing the endianness.



Thank you very much for your answer.

I am testing 2 OPC servers and 2 OPC clients.

Server 1: Siemens TP700 Comfort Panel (opc.tcp://
Server 2: Anybus AB7570-F (opc.tcp://

Client 1: UaExpert
Client 2: OPC UA Client

Both clients can connect to Server 1. The way to see the tags and its values is slightly different, but I get it with no problem. So I discard any IP or network configuration problem. The endianness is correct. I can see the values as in the HMI.

Client 1 connects to Server 2. I can also get the tags and see its values, but endianness is wrong.

Client 2 also connects to Server 2. But I cannot find a way to get the tags. I can neither find any configuration or any other thing I can change.

Relating the serial number:



Thanks again in advance!


What exactly is Client 2? What is the specific hardware/software?


I am running the OPC Clients in my Windows PC. That is the hardware.

And I just wanted to point out that we are using 2 different clients. The number is meaningless. Client 2 is a free OPC Client software we have found in internet:


I will describe the situation the best I can:

I work in the R&D department of a factory. We sell machines to customers, and customers are starting to ask for an OPC server in our machines.

We have used the Siemens TP700 Comfort HMI as an OPC server in a couple of machines. We have tested it with the free OPC Client and it works fine.

But using TP700 as OPC server has the problem that the internal network of our machine is linked to the customer’s LAN. In order to isolate both networks, we can use a switch or we can use a Gateway. So we want to use your Gateway as an OPC server, and I want to be sure it can be acceded from any OPC Client.

I have tried the same OPC Client from “integrationobjects” and it does not work. Then I have used the UaExpert, following your documentation. And it works but with the endian problem.

So at this moment I cannot install your Gateway in my machine, as I cannot tell the customer how to connect and receive the information.

Any help from you will be apreciated. And if you need more information pease ask me.

Thank you very much.


You should be able to use this device for your use case, but I am going to need to investigate these issues you are having a little further. In the US we are now leaving for the Thanksgiving holiday until Monday, but it appears that you are in the UK, so I would recommend also creating a ticket at (Our official support channel) where you should be able to get more immediate help with this issue.