iFix Number Comparison

Please see code below----

Hey guys! My programming skills is very poor and hence which is why I need your input. Basically I am making sure that the Open Value(DSP tag) is greater than Close Value(WSP tag) and if that is not the case then throw an error message. At the moment DSP tag placeholder accepts the value even if its less than WSP. I know that this can be easily handled by a PLC but our client wants to do it virtually as they don't want us to touch there PLC program. Write is enabled so I can write into this tag. So instead of accepting the value it should instead throw an Error.

Thanks for your help.
Faisal

Private Sub Dev1StopLevel8_Click()
Dim OPENVAL As Double
Dim CLOSEVAL As Double
OPENVAL = READVALUE("Fix32.COLPSN02.COL-MTI-G-2001-DSP.F_CV")
CLOSEVAL = READVALUE("Fix32.COLPSN02.COL-MTI-G-2001-WSP.F_CV")
If OPENVAL < CLOSEVAL Then
MsgBox "error"
Else
MsgBox "GOOD"
End If

End Sub

Here is something else I tried but problem is the .F_CV value gets updated. Your help is greatly appreciated.

Dim Setp_err As Boolean
Setp_err = False

If (readvalue("Fix32.COLPSN02.COL-MTI-G-2001-WSP.F_CV", 0) <> "---") Then
If readvalue("Fix32.COLPSN02.COL-MTI-G-2001-DSP.F_CV") < readvalue("Fix32.COLPSN02.COL-MTI-G-2001-WSP.F_CV") Then
MsgBox "Invalid Entry! Open Gate value should be greater than Close Gate Value", vbExclamation
Setp_err = True
End If
End If

'If Setp_err = False Then 'If Open Value is greater than Close Value then update filed with current Value
'Dim HighEGU As String
' HighEGU = readvalue("Fix32.COLPSN02.COL-MTI-G-2001-DSP.A_EHI")
'WRITEVALUE HighEGU, "Fix32.COLPSN02.COL-MTI-G-2001-DSP.F_CV", 2
'End If