Modbus TCP Client: query multiple requests

Networking Solutions
1

I use the Modbus TCP Client to request data from a modbus device (PLC).

The PLC stores 5 32-bit INT values in its register. They are stored in address 1 to 10. When I request all of them at once, I get the 5 values as expected.

However, when I request them one by one (with 5 requests) then I only get the first value and the others fail.

3

Greetings, gguns,

Thank you for your message.

To better understand what’s happening, could you please clarify the following:

  • How exactly are you sending the requests? (e.g., via Data to Server, a custom script, an external application, etc.)
  • Are you seeing any specific error messages or logs when the requests fail?

This information will help us narrow down the root cause and guide you more effectively.

Looking forward to your reply.

Best regards,
V.

4

I use Modbus TCP Client to request data from a PLC

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In the above screenshot I request all the data registers in one request. that works fine.

When I want to request the individual parameters (row 1 to 5) I only get the first value (crates_client). The other requests result in a “Failed request”.

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5

Greetings,

Thank you for the screenshots.

To fully reproduce the issue on my end, could you please let me know which firmware version your device is running? Having the exact version will help us continue the troubleshooting more accurately.

Looking forward to your reply.

Warm regards,
V.

6

I’m running RUT2M_R_00.07.18.3 on a RUT241

7

Greetings,

Thank you for your message,

Can you confirm that all of the requests are configured correctly? You can simply test each request one by one just bellow the Add new request section.

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Please let me know how it goes,

Warm regards,
V.

8

Yes, if I test them one by one manually then they work fine.

9

Thank you for clarification,

For troubleshooting purposes, we will require more sensitive information from your end, such as the troubleshoot file, which may contain passwords, public IP addresses, serial numbers, and such. To avoid leaking this information, we have sent you a form to fill out, which you will receive in your e-mail inbox that you have registered your account with in the forums. In the Ticket ID field of the form, please enter the ID of this thread, which is 16562.

Thank you,

V.