RS232: IRP_MJ_WRITE error

Discussion in 'General Electronics Chat' started by anhnha, Apr 11, 2015.

  1. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
    I am doing a project and need to communicate between an application
    on computer with PLC through RS232 port.
    The app send "1" or "0" to PLC. However, sometimes PLC doesn't receive
    that. To check what is happening I used AccessPort to monitor.
    I am not at work right now, so I can't have the log file but it is
    something like the one below.

    As you can see in the line #34, the "Result" is nothing and "Time" is 0.00000000.
    However, "Data" is still OK ("1" in this case).
    Where is the problem in this case?
    Is that the app sending is OK because "Data" from the AccessPort is still OK.
    The problem is that this data doesn't come to PLC.

    Code (Text):
    2. #           Time        Process          Request           Port   Result  Other
    3. 33      0.00002222      app.exe       IRP_MJ_WRITE       Serial0 SUCCESS Data: 1
    4. 34      0.00000000      app.exe       IRP_MJ_WRITE       Serial0         Data: 1
    5. 35      0.00000562      app.exe       IRP_MJ_READ        Serial0 SUCCESS Data: 0
    6. 36      0.00000239      app.exe       IRP_MJ_READ        Serial0 SUCCESS Data: 0
    Last edited: Apr 11, 2015
  2. anhnha

    Thread Starter Well-Known Member

    Apr 19, 2012
    What is the "Time" means here?
    In line #34, Data is 1. Does this mean that the app has completed its task to write that data to RS232 buffer?
    I would like to know where the problem come from, the app, PLC or computer driver.