Modbus RTU comunication issue

Forum Home Forums Communicating with Devices Modbus Modbus RTU comunication issue

Viewing 14 posts - 1 through 14 (of 14 total)
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  • #5565
    Avatarcooldjmc
    Participant

    Hi, i’m getting a comunication issue in Comunicator after some modbus rquests that are workink ok, i get this error messages:

    2019-06-17 17:00:09 Communication session with the Device 4 “Compresor 4”, type: KpModbus, call number: 4
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (5/5): 04 03 BA 00 00
    Receive (186/186): 00 5C 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 01 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 28 00 24 00 1F 00 00 01 87 00 00 00 0C 00 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 15 00 12 00 02 00 08 00 28 00 2C 00 25 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 E2 01 4B 00 00 00 05 00 00 00 00 02 03 02 03 00 00 00 00 00 00 00 39 00 00 00 00 00 00 00 00 00 00 00 4B 00 00 00 00 00 00 00 00 00 00 00 17 00 00 00 00 13 70
    OK!

    2019-06-17 17:00:10 Communication session with the Device 4 “Compresor 4”, type: KpModbus, call number: 4
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (5/5): 04 03 BA 00 00
    Receive (186/186): 00 5C 00 01 00 01 00 00 3F 3F 00 00 00 01 02 00 00 00 00 00 00 01 00 01 00 01 00 3F 3F 3F 3F 01 00 01 00 00 00 00 00 00 00 00 00 01 00 28 00 24 00 1F 00 00 01 87 00 00 00 0C 00 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 3F 3F 00 00 00 00 00 00 01 02 04 08 00 00 00 00 00 00 00 80 00 00 00 00 00 00 00 15 00 12 00 02 00 08 00 28 00 2C 00 25 00 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 E2 01 4B 00 00 00 05 00 00 00 00 02 03 02 03 00 00 00 00 00 00 3F 3F 00 39 00 00 00 00 00 00 00 00 00 08 00 4B 00 00 00 00 00 00 00 00
    CRC error!
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!

    2019-06-17 17:00:14 Communication session with the Device 4 “Compresor 4”, type: KpModbus, call number: 4
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (5/5): 04 3F 3F 03 BA
    Incorrect PDU function code
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!

    2019-06-17 17:00:18 Communication session with the Device 4 “Compresor 4”, type: KpModbus, call number: 4
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!
    Request element group “Comp-DATA”
    Send (8): 04 03 00 00 00 5D 84 66
    Receive (0/5):
    Communication error!

    2019-06-17 17:00:23 Communication session with the Device 4 “Compresor 4”, type: KpModbus, call number: 4
    Request element group “Comp-DATA”
    2019-06-17 17:00:23 Error communicating with Device 4 “Compresor 4”: Error writing data: Uno de los dispositivos conectados al sistema no funciona.

    2019-06-17 17:00:23 Close serial port COM4

    2019-06-17 17:00:23 Open serial port COM4
    2019-06-17 17:00:23 Error executing the communication channel actions before session with a device: Error opening serial port: Access to the port ‘COM4’ is denied.

    2019-06-17 17:00:23 Unable to communicate with Device 4 “Compresor 4” because connection is not established

    2019-06-17 17:00:24 Open serial port COM4
    2019-06-17 17:00:24 Error executing the communication channel actions before session with a device: Attempt to open serial port can not be earlier than 5 seconds after the previous.

    2019-06-17 17:00:24 Unable to communicate with Device 4 “Compresor 4” because connection is not established

    2019-06-17 17:00:24 Open serial port COM4
    2019-06-17 17:00:24 Error executing the communication channel actions before session with a device: Attempt to open serial port can not be earlier than 5 seconds after the previous.

    2019-06-17 17:00:24 Unable to communicate with Device 4 “Compresor 4” because connection is not established

    2019-06-17 17:00:24 Open serial port COM4
    2019-06-17 17:00:24 Error executing the communication channel actions before session with a device: Attempt to open serial port can not be earlier than 5 seconds after the previous.

    #5567
    MikhailMikhail
    Moderator

    Hi,

    How the devices are physically connected to Rapid SCADA server?

    #5569
    Avatarcooldjmc
    Participant

    Hi, are conected with USB to Rs485 converters, there are 2, each one conected to a USB port on the mainboard. Each converter pulls 2 RTU Slaves. But the test i made is only with one slave active.

    #5575
    MikhailMikhail
    Moderator

    The log says that there are problems with a converter:

    2019-06-17 17:00:23 Open serial port COM4
    2019-06-17 17:00:23 Error executing the communication channel actions before session with a device: Error opening serial port: Access to the port ‘COM4’ is denied.

    #5576
    MikhailMikhail
    Moderator

    May be other application uses the same port COM4.

    #5582
    Avatarcooldjmc
    Participant

    Thank you for your answers. what i don’t understand is after this:
    2019-06-17 17:00:23 Communication session with the Device 4 “Compresor 4”, type: KpModbus, call number: 4
    Request element group “Comp-DATA”
    2019-06-17 17:00:23 Error communicating with Device 4 “Compresor 4”: Error writing data: Uno de los dispositivos conectados al sistema no funciona.

    2019-06-17 17:00:23 Close serial port COM4

    the COM port remains blocked and no other app can open it, also if i try restart the computer it won’t restart remains on “Shutting down windows ” screen and i must reset it.

    #5585
    MikhailMikhail
    Moderator

    Seems like hardware problem. What USB-COM converter do you use?

    #7197
    Avatarhethongscada62
    Participant

    Dear Mr. Mikhail.
    I am creating a new project “Smart ScadaFarm” on Raspberry Pi4. It is running but not unstable. Maybe all my devices are connecting to RaspberryPi4-server via Rs485-WiFi converter. Is that the cause of instability?.
    Now i want that all these devices will be connected to Raspberry Pi4 via RS485-USB converter. Can they connect to Pi4? How will i configure?
    Thanks and best regards

    #7199
    MikhailMikhail
    Moderator

    Hello,

    Is that the cause of instability?

    You should provide communication logs to check.

    Can they connect to Pi4?

    Depends on the converter. I can’t suggest a particular. As I know, many of them work with RPi.

    #7316
    Avatarkumajaya
    Participant

    I recently have a bad experience with Moxa NPort device for transmit Modbus RTU over ethernet in RFC2217 mode. I have to compile Moxa Real COM driver for a stable communication. Working flawlessly after.

    #7325
    MikhailMikhail
    Moderator

    Using Moxa NPort, I prefer TCP server or TCP client mode.

    #7905
    Avatarkumajaya
    Participant

    @Mikhail Today I realized how simple NPort in TCP mode. Thank you.

    Not actually NPort device I use here but a GSM modem from Moxa with a serial port. With a private IP from GSM operator, the only option to access it is via OnCell Central Manager. OCM map the serial port to a local TCP port.

    #7908
    MikhailMikhail
    Moderator

    If you use GSM modems, you can try a mode when Communicator is TCP server, and a modem is TCP client, so a modem doesn’t need static IP address.

    #7923
    Avatarkumajaya
    Participant

    I’ll try it @Mikhail. For now I accessed it from Node-RED using node-red-contrib-modbus. I have to enable TCP in telnet mode because got incorrect Modbus stream in default TCP mode.

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