Write register window edit wrong address

[ghostolo90]

When I try to write a register, the new value is set on the address-1.

Same behaviour on both coil status and holding register.

Steps to reproduce:

• Double click on a value to write or its address
  

• Edit the value and press OK
  

• The value edited is set on the address -1
  

[sanny32]

Please test at version 1.9.0

[ghostolo90]

Done, not working.

[sanny32]

Sorry, can’t reproduce.
Can you add video that reproduce bug?

[ghostolo90]

Hi, here is the video

2025-03-06_09h07_00.mp4

[sanny32]

Can you tell me what is modbus server used? A device or a simulator program?

[ghostolo90]

Yes, i'm using a Beckhoff PLC

[sanny32]

Please follow the steps below

1. Connect to your modbus device
2. Open Display Definition dialog (menu Setup ->Data Definition) and set Scan Rate to 10000
3. Through the menu Setup -> Text Capture make a log.txt file

5. Make a write to registers
6. Through the menu Setup -> Capture Off stop a log capture
7. Upload log.txt file here

[ghostolo90]

Hello,
Done, log and video attached.

log.txt

2025-03-10_13h11_44.mp4

[sanny32]

Hello @ghostolo90. Thanks for what you did to understand how the bug occurred.
Based on the log data I see that you send WRITE SINGLE REG request to address 30 (0-based).

Then, application send READ HOLDING REGS request to read 31 holding registers data that starts at address 0 (0-based)

The response from the server returns the value at 29 address (0-based)

I suppose that problem at the modbus server.