When many similar frames are being processed it may be wasteful to estimate the FWHM independently for each arc frame. In this case it may be set manually using FIGARO SETOBJ
SETOBJ object=/rdn-fil/MORE.ECHELLE.WAVE_FIT_1D.LINE_WIDTH value=/nn.n/
at the system command prompt, where /nn.n/ is expressed in pixels and is twice the required FWHM.
Martin Clayton