Modifying chart trendline without activating sheet

[MrPez]

I have some code that updates trendlines on a chart. The code runs fine if the sheet with the chart is active, but not if another sheet is active (which will be the case).

I get Type Mismatch on the highlighted line. Any ideas?

Sub Trendline_Update()Dim PVTrend As String
Dim EITrend As String
Dim PVType As String
Dim EIType As String
Dim STPChart As Chart
Dim DetNo As Worksheet
'Updates trendlines in DR report according to the PV/EI-dose relationship determined by the DRAnalysis code


For i = 1 To 2


    If i = 1 Then Set DetNo = Worksheets("Detector1_Report")
    If i = 2 Then Set DetNo = Worksheets("Detector2_Report")


    Set STPChart = DetNo.ChartObjects("Chart 1").Chart
    
    PVTrend = Range("M30")
    EITrend = Range("M31")
    
    Select Case PVTrend
        Case Is = "Linear"
            PVType = xlLinear
        Case Is = "Polynomial (2nd order)"
            PVType = xlPolynomial
        Case Is = "Power"
            PVType = xlPower
        Case Is = "Logarithmic"
            PVType = xlLogarithmic
        Case Is = "Exponential"
            PVType = xlExponential
    End Select
    
    Select Case EITrend
        Case Is = "Linear"
            EIType = xlLinear
        Case Is = "Polynomial (2nd order)"
            EIType = xlPolynomial
        Case Is = "Power"
            EIType = xlPower
        Case Is = "Logarithmic"
            EIType = xlLogarithmic
        Case Is = "Exponential"
            EIType = xlExponential
    End Select
    
    With STPChart
[COLOR=#ff0000]        .SeriesCollection("PV").Trendlines(1).Type = PVType[/COLOR]
        .SeriesCollection("PV").Trendlines(1).DataLabel.Font.ColorIndex = 49
        .SeriesCollection("EI").Trendlines(1).Type = EIType
        .SeriesCollection("EI").Trendlines(1).DataLabel.Font.ColorIndex = 9
    End With
    
Next i


End Sub

 

[MrPez]

Slightly narrowing the problem down:

Getting

print stpchart.Name

shows that STPChart is named as
"[ActivesheetName] Chart 1"
instead of
"Detector1_Report Chart 1"

I don't know what this is!

 

[MrPez]

nevermind, was me being daft.
Should have been

[COLOR=#333333]PVTrend = DetNo.Range("M30")[/COLOR]