How could i get a Plot with a Xaxis in volt by the ocean script?

Hello

I'm trying to get a plot by the ocean script but when i observe my 3 outputs signals i have 3 lines (constant) whereas when i lauch that by a classical simulation (interface analog environment) i obtain the correct waveform with the Vn in horizontal scale

Indeed, i think i have a trouble on my Xaxis because in one case (by the analog environment) "Vn" (my sweep variable from 0 to 1.1) is on the X axis and on the other case, i have nothing, the time i think...

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ocnWaveformTool( 'wavescan )
simulator( 'spectre )
design(     "/../spectre/schematic/netlist/netlist")
resultsDir( "/../spectre/schematic" )
definitionFile(
    "models.scs"
)
analysis('dc ?saveOppoint t  ?param "Vn"  ?start "1.1"
        ?stop "0"  ?lin "1000"  )

desVar(      "Vn" 1    )
temp( 27 )
run()
selectResult( 'dcOp )
plot(getData("/S") getData("/SB") getData("/BL") )

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thank you for your answer and sorry for my "basic" english