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VBA WITH AB PLC

VBA WITH AB PLC

VBA WITH AB PLC

(OP)
Does anyone have some sample macro's that they can share with me help me get started

RE: VBA WITH AB PLC

Hey RAGEE.

I designed a VB 6.0 HMI which interfaces with a SLC. A PLC-5 would be the same. Do a search in your RsLogix help for DDE (Dynamic Data Exchange). This is what you use to exchange data between your PLC and VB. There is example VB code in the help topics which tell you how to write(LinkPoke) data to a PLC or read (LinkRequest) from your PLC. The catch is that you need the full version of RSLinx OEM (about $1000) to do it. Linx Lite that comes with Logix won't support DDE. Also, if you are exchanging tons of data, DDE causes a noticable drag on your HMI also.

Their is also another option. http://www.plcdriver.com/ . These guys have an Allen Bradley OPC (OLE for Process Control) Server that is much faster and about $400 cheaper. If you download their ActiveX control it all but eliminates the VB code. Their help files are quite useful, suprisingly , and I learned everything I needed to know from them.

Hope this helps you out. It pretty much came down to whether the data was worth the money. The OPC Server has a free download that has full functionality but runs for only 2 hours. Check it out and see what you think. Good Luck

RE: VBA WITH AB PLC

When you say VBA, I assuming you are asking for an Excel Macro


Here is one I wrote:


Sub Start()

Dim lngRow As Long
Dim varCycle As Variant
Dim varLogging As Variant
Dim varResults As Variant
On Error GoTo Error
    
 
    'opens a COLD DDE link
    RSIchan = DDEInitiate("RSLinx", "M1138")
    
    'assign PLC bit values to VB variant varibles
    varLogging = DDERequest(RSIchan, "B3/163")
    varCycle = DDERequest(RSIchan, "B3/161")
    
    'close COLD DDE link
    DDETerminate (RSIchan)
    
    'check to see if the Cycle bit went to "1" if it did, excute read data
    If varCycle(1) = "1" And varLogging(1) = "1" Then

        'starts at row 3 of sheet
        lngRow = 3
        
        If Range("INDATA!A3").Value > 3 Then
            'look up last cell and change position
            lngRow = Range("INDATA!A3").Value
        End If
        
        'check until end of sheet
        For lngRow = lngRow To 65500
            'look for next empty cell
            If Cells(lngRow, 1) = "" Then Exit For
            
            'write current cell location to sheet INDATA
            'rather than writing a loop to search on
            'every cycle, by the time the log is at row 21,500
            'it could take a long time to search the rows...
            Range("INDATA!A3").Value = lngRow + 1
                        
        'add 1 to row "x" to check next row
        Next
          
        'opens a COLD DDE link
        RSIchan = DDEInitiate("RSLinx", "M1138")
        
        'there might be a better way to do this like
        'using this somehow ???????? but I don't know how
        'data = DDERequest(RSIchan, "f11:0,L7,C7")
        'Range("[M1138.xls]LOG!R[x]C1:R[x]C7").Value = data
                                                        
     
        'read word F8:10 and load into a VB variant variable
        f810data = DDERequest(RSIchan, "F8:10")
        'read word F8:11 and load into a VB variant variable
        f811data = DDERequest(RSIchan, "F8:11")
        'read word F8:12 and load into a VB variant variable
        f812data = DDERequest(RSIchan, "F8:12")
        'read word F8:16 and load into a VB variant variable
        f816data = DDERequest(RSIchan, "F8:16")
        'read word F8:18 and load into a VB variant variable
        f818data = DDERequest(RSIchan, "F8:18")
        'read word F8:17 and load into a VB variant variable
        f817data = DDERequest(RSIchan, "F8:17")
        'read word F8:20 force check #1 and load into a VB variant variable
        f820data = DDERequest(RSIchan, "F8:20")
        'read word F8:21 force check #2 and load into a VB variant variable
        f821data = DDERequest(RSIchan, "F8:21")
        'read word F8:22 force check #3 and load into a VB variant variable
        f822data = DDERequest(RSIchan, "F8:22")
        'read word F8:23 force check #4 and load into a VB variant variable
        f823data = DDERequest(RSIchan, "F8:23")
        'read word F8:24 max force and load into a VB variant variable
        f824data = DDERequest(RSIchan, "F8:24")
        'read word F8:25, get PASS or FAIL status from PLC and load into a VB variant variable
        varResults = DDERequest(RSIchan, "F8:25")
        
        'close COLD DDE link
        DDETerminate (RSIchan)
        
        'write all values to cells
        Cells(lngRow, 1).Value = f810data
        Cells(lngRow, 2).Value = f811data
        Cells(lngRow, 3).Value = f812data
        Cells(lngRow, 4).Value = f816data
        Cells(lngRow, 5).Value = f818data
        Cells(lngRow, 6).Value = f817data
        Cells(lngRow, 7).Value = f820data
        Cells(lngRow, 8).Value = f821data
        Cells(lngRow, 9).Value = f822data
        Cells(lngRow, 10).Value = f823data
        Cells(lngRow, 11).Value = f824data
        
            Range("INDATA!A4").Value = varResults
            
            If Range("INDATA!A4").Value = 0 Then
               Cells(lngRow, 12).Value = "PASS"
               
                'copies the conditional format to the next cell
                Rows(lngRow + 1).Select
                Selection.Copy
                Rows(lngRow + 2).Select
                ActiveSheet.Paste
                Application.CutCopyMode = False
                Range("L" & lngRow + 2).Select
                
            End If
            
            If Range("INDATA!A4").Value = 1 Then
                Cells(lngRow, 12).Value = "HEIGHT FAIL"
                
                'copies the conditional format to the next cell
                Rows(lngRow + 1).Select
                Selection.Copy
                Rows(lngRow + 2).Select
                ActiveSheet.Paste
                Application.CutCopyMode = False
                Range("L" & lngRow + 2).Select
                
            End If
            
            If Range("INDATA!A4").Value = 2 Then
                Cells(lngRow, 12).Value = "PARALLEL FAIL"
                
                'copies the conditional format to the next cell
                Rows(lngRow + 1).Select
                Selection.Copy
                Rows(lngRow + 2).Select
                ActiveSheet.Paste
                Application.CutCopyMode = False
                Range("L" & lngRow + 2).Select
              
            End If
            
            If Range("INDATA!A4").Value = 3 Then
               Cells(lngRow, 12).Value = "FORCE FAIL"
               
                'copies the conditional format to the next cell
                Rows(lngRow + 1).Select
                Selection.Copy
                Rows(lngRow + 2).Select
                ActiveSheet.Paste
                Application.CutCopyMode = False
                Range("L" & lngRow + 2).Select
                
            End If
            
            If Range("INDATA!A4").Value > 3 Then
                Cells(lngRow, 12).Value = "ERROR!"
            End If
        
        'capture time and date stamp into column 8
        Cells(lngRow, 13).Value = Now()
 
        'scrolls the screen down automatically
        'Range("A" & lngRow + 1).Select
      
    End If

GoTo Done:
Error:
    frmError.Hide
    frmError.Show
 
    'trying a timed form box, so disabled the old MESSAGE BOX here for now
    'MsgBox ("Communications to PLC have been lost! Or Log Sheet is FULL! Can not log data anymore. Check PLC connection and wiring.")
    Application.Run Macro:="ChkTime"

Done:

'check for date change, if so then save as new sheet
Application.Run Macro:="ChkTime"
End Sub


You can download the whole program here:

http://www.mrplc.com/dl/index.php?action=view&view=entry&entryid=74



Or if you want a sample VB 6.0 AB to DDE program you can donwload a sample program I never did finish, but the DDE works in the program.


http://www.mrplc.com/dl/index.php?action=view&view=entry&entryid=58


The code for the above program looks a little bit different than VBA code, so make sure you get the right sample.


Good Luck!

Chris Elston
Automation & Controls Engineer
http://www.mrplc.com
Download Sample PLC Ladder Logic Code
at MrPLC.com

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