Strange values being read from PLC

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Mickey
2013-02-07
2013-05-30
  • Mickey
    Mickey
    2013-02-07

    I'm using Advanced HMI to read string values from the PLC. Occasionally, I haven't been able to narrow down an exact time this happens; nor have I been able to consistently replecate the issue, the values I get back from the PLC are not the string values held by a specific tag, but instead are a string of nonsensical numbers that almost look sequential, but are not in fact sequential.  Has anyone else ran accross this?

    Here is the code I'm using to read the values.

    For i = 0 To 23
                Try
                    t = frm_Main.EthernetIPforCLXComm1.ReadAny(Formula_List(i))  ' Read value to temp var
                    If isFormulaValid(t, CompoundNumber) Then  'checking to see if the value read from plc is valid based on known list of formulas that can be ran.
                        If t <> "" Then     'if not empty show but disable dropdown list.
                            With ControlArray(i)
                                .Enabled = False
                                .SelectedText = t
                            End With
                        Else
                            ControlArray(i).Enabled = True
                        End If
                    Else
                        With ControlArray(i)
                            .Text = ""                         'value recieved wasn't valid so make item ""
                            .Enabled = True
                        End With
                    End If
                Catch ex As Exception
                    MessageBox.Show(ex.ToString)
                End Try
            Next
    

    I recently added the code to make list item "" if formula isn't valid, however it does not address the problem of the erroneous values being read. Do you have any suggestions?

    Thanks,

    Mickey

     
  • Mickey
    Mickey
    2013-03-04

    Hey Archie,

       Just wanted to check in with you and see if you might have thought of any reason why this is happening, or possibly any ideas that I could try that would help test the issue further.

    Thanks,

    Mickey

     
  • Archie
    Archie
    2013-03-04

    Are you using version 3.26? Prior versions had a known issue with transaction numbers when communication was heavy that could cause the problem you describe.

     
  • Mickey
    Mickey
    2013-03-04

    I'm using the AdsvancedHMIbetav326.zip file that's available here.  The Release notes are for V322, however. there is also a notes 324.?

    Now that you mention issues with heavy communication I do remember getting a couple of errors when I was testing where the read failed due to timeout.  I didn't think much about it before.

     

  • Anonymous
    2013-03-19

    I'm having this issue with the EthernetIPforCLXComm driver also. It appears that I've followed almost the same troubleshooting path as you as well, kf4ozb. I'm using a few of the components on a form as well as having a ReadAny() call to pull in a 100 member array in the form's code. In my case once I get the SequenceNumber returned rather than the array I have to kill and restart the program to get valid responses again.

    I've posted about it in the AdvancedHMI forum at http://advancedhmi.com/forum/index.php?topic=15.0

     
  • Archie
    Archie
    2013-05-13

    Version 3.27 has addressed many issues with the EthernetIPforCLX driver. I would try that version to see if it resolves these issues.