I figured it out by myself. Here the code snipped, which did the trick:
i=0
SetActiveSource(rTT_)
tsteps = rTT_.TimestepValues
PlotOverLine1 = PlotOverLine(Input=passArrays1, Source='High Resolution Line Source')
Data = Show()
view = GetActiveView()
j=0
i=i+1
for TimeStepNum in range(len(tsteps)):
view.ViewTime = tsteps[TimeStepNum]
PlotOverLine1.Source.Point1 = [l1[j],0.0,T]
PlotOverLine1.Source.Point2 = [l1[j],B,T]
Render()
writer = CreateWriter("Export"+str(i)+".%d.csv" %(TimeStepNum), PlotOverLine1)
#writer.FieldAssociation = "Point Data"
writer.UpdatePipeline()
Render()
del writer
j=j+1
For clarification:
rTT_ is the name of my unstructured grid reader and passArrays1 is a filter for the desired quantities I want to write (speeds up the whole process). In variable l1, the coordinate (in x-direction) of the line plot was pre defined for every time step.
I hope this might help someone in the future.
Kind regards,
Lukas