Closed serial port

[qwertyqwq]

Hello,
I installed RapidSCADA yesterday and just started learning it. I have a slave device that works with Modbus RTU. Using this device, I measure temperature data from 4 NTC sensors. I configured the parameters in the Administrator application as described in the tutorial. At first, communication between my slave device and PC was successful.

However, after the slave device was powered off and on again, I was no longer able to establish communication through the Administrator application. On the other hand, when I use Modbus test software, I can successfully communicate over the same COM port and the same USB channel.

Below, I share the Line State log. As you can see, after the message “Close serial port COM3”, the connection to COM3 cannot be opened again. Could you please tell me how to resolve this issue? Restarting the computer did not help.

Also, in the Instance Status section, while the Server shows as “Normal,” the Communicator gives an “Error.” Executing commands such as restart does not make any difference.

LINE LOG:

2025-08-25 14:51:06 Session with the device [1] NTC Daughter Board
Request element group “Temperature Meausement”
Send (8): 05 03 00 01 00 04 14 4D
Receive (2/2): 05 03
Receive (11/11): 08 FF EC FF EC FF EC FF EC D6 69
OK

2025-08-25 14:51:06 Session with the device [1] NTC Daughter Board
Request element group “Temperature Meausement”
Send (8): 05 03 00 01 00 04 14 4D
Receive (2/2): 05 03
Receive (11/11): 08 FF EC FF EC FF EC FF EC D6 69
OK

2025-08-25 14:51:06 Close serial port COM3

2025-08-25 14:51:06 Communication line [1] RTU 485 is stopped

LINE STATE:

[1] RTU 485
———–
Status : Terminated
Communication channel : COM3, closed

Shared Data (1)
—————
Modbus.Templates = Dictionary of 1 templates

Devices (1)
———–
[1] NTC Daughter Board : Undefined

[manjey73]

What operating system is used? Which physical port is being used? (device)

[qwertyqwq]

I am using Windows 10 Pro on my computer. For the physical interface, I am using a classic USB-RS485 converter.

• This reply was modified 4 hours, 8 minutes ago by qwertyqwq.

[Mikhail]

Hi,
The software should try to open the port when it is available. What is in the log?

[Mikhail]

If another software opens the port, it cannot be opened by Rapid SCADA.

[qwertyqwq]

Thank you for your response.
I’m absolutely sure that no other software is using the COM port.
I’ve created a new project many times. At the beginning, when I set up the serial port, I can see the data flow working correctly on the administrator application.
However, as soon as I configure the Channels and upload the code, I notice that COM3 is closed, but it does not reopen again.

I’m sharing the log and text record from Communicator here.
This part is after I uploaded the software.
Even so, in the Line State and Line Log tabs, nothing changes or new entries appear after the upload.
The message saying that the COM port is closed always remains as the last message.

This is SCADACOMM.log
2025-08-26 15:30:20 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Start logic processing
2025-08-26 15:30:20 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Driver DrvCnlBasic 6.1.0.1 loaded from file C:\Program Files\SCADA\ScadaComm\Drv\DrvCnlBasic.Logic.dll
2025-08-26 15:30:20 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Driver DrvDsScadaServer 6.0.1.1 loaded from file C:\Program Files\SCADA\ScadaComm\Drv\DrvDsScadaServer.Logic.dll
2025-08-26 15:30:20 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Driver DrvModbus 6.0.0.4 loaded from file C:\Program Files\SCADA\ScadaComm\Drv\DrvModbus.Logic.dll
2025-08-26 15:30:20 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Data source ScadaServer initialized successfully
2025-08-26 15:30:20 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Data source ScadaServer: Receive the configuration database
2025-08-26 15:30:23 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ERR] Data source ScadaServer: Error checking server connection:
Invalid username or password
2025-08-26 15:30:23 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ERR] Unable to start communication lines because the configuration database is not received
2025-08-26 15:30:30 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ACT] Data source ScadaServer: Receive the configuration database
2025-08-26 15:30:33 [DESKTOP-M2JC1C1][DESKTOP-M2JC1C1$][ERR] Data source ScadaServer: Error checking server connection:
Invalid username or password

SCADACOMM.txt

Communicator
————
Started : 26/08/2025 15:30:20
Execution time : 00:00:46
Status : Error
Version : 6.2.0.1

Data Sources (1)
—————-
[ScadaServer] Server Data Source : Ready

Server Data Source
——————
Connection : Not Used
Current data queue : 0 of 1000, skipped 0
Historical data queue : 0 of 1000, skipped 0
Event queue : 0 of 1000, skipped 0

Communication Lines (0)
———————–
No lines

[manjey73]

Data source ScadaServer: Error checking server connection:
Invalid username or password

You probably changed the login and password of the application, and your device does not connect to the server and cannot receive data. Accordingly, it is not loaded for execution and does not open the port.

[qwertyqwq]

Yes, thank you, I solved the previous issue. I added the passwords I had set for Communicator and WebStation to the Users section and granted all of them Administrator privileges.

However, I have another question. Right now, I am unable to upload because I changed the Username and Password in the Agent connection. I have also added these new Username and Password values to the Users section, but I still cannot upload. Could you please guide me?

[qwertyqwq]

Im using 6.2.1.3 version

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