VBA WITH AB PLC

[RAGEE]

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

 

[klysitt]

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

 

[chakorules]

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&quot

'assign PLC bit values to VB variant varibles
varLogging = DDERequest(RSIchan, "B3/163&quot
varCycle = DDERequest(RSIchan, "B3/161&quot

'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&quot.Value > 3 Then
'look up last cell and change position
lngRow = Range("INDATA!A3&quot.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&quot.Value = lngRow + 1

'add 1 to row "x" to check next row
Next

'opens a COLD DDE link
RSIchan = DDEInitiate("RSLinx", "M1138&quot

'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&quot
'Range("[M1138.xls]LOG!R[x]C1:R[x]C7&quot.Value = data


'read word F8:10 and load into a VB variant variable
f810data = DDERequest(RSIchan, "F8:10&quot
'read word F8:11 and load into a VB variant variable
f811data = DDERequest(RSIchan, "F8:11&quot
'read word F8:12 and load into a VB variant variable
f812data = DDERequest(RSIchan, "F8:12&quot
'read word F8:16 and load into a VB variant variable
f816data = DDERequest(RSIchan, "F8:16&quot
'read word F8:18 and load into a VB variant variable
f818data = DDERequest(RSIchan, "F8:18&quot
'read word F8:17 and load into a VB variant variable
f817data = DDERequest(RSIchan, "F8:17&quot
'read word F8:20 force check #1 and load into a VB variant variable
f820data = DDERequest(RSIchan, "F8:20&quot
'read word F8:21 force check #2 and load into a VB variant variable
f821data = DDERequest(RSIchan, "F8:21&quot
'read word F8:22 force check #3 and load into a VB variant variable
f822data = DDERequest(RSIchan, "F8:22&quot
'read word F8:23 force check #4 and load into a VB variant variable
f823data = DDERequest(RSIchan, "F8:23&quot
'read word F8:24 max force and load into a VB variant variable
f824data = DDERequest(RSIchan, "F8:24&quot
'read word F8:25, get PASS or FAIL status from PLC and load into a VB variant variable
varResults = DDERequest(RSIchan, "F8:25&quot

'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&quot.Value = varResults

If Range("INDATA!A4&quot.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&quot.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&quot.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&quot.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&quot.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.&quot
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