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COMEDI_TO_PHYS(3) Comedi reference COMEDI_TO_PHYS(3)


comedi_to_phys - convert sample to physical units


#include <comedilib.h>

double comedi_to_phys(lsampl_t data, comedi_range * range, lsampl_t maxdata);


Converts parameter data given in sample values (lsampl_t, between 0 and maxdata) into physical units (double). The parameter range represents the conversion information to use, and the parameter maxdata represents the maximum possible data value for the channel that the data was read. The mapping between physical units is linear and assumes ideal converter characteristics.

Conversion of endpoint sample values, that is, sample values equal to 0 or maxdata, is affected by the Comedilib out-of-range behavior (see function comedi_set_global_oor_behavior). If the out-of-range behavior is set to COMEDI_OOR_NAN, endpoint values are converted to NAN. If the out-of-range behavior is set to COMEDI_OOR_NUMBER, the endpoint values are converted similarly to other values.

If there is an error, NAN is returned.


David Schleef <>

Frank Mori Hess <>


Herman Bruyninckx <>


Bernd Porr <>


Ian Abbott <>


Éric Piel <>



Copyright © 1998-2003 David Schleef
Copyright © 2001-2003, 2005, 2008 Frank Mori Hess
Copyright © 2002-2003 Herman Bruyninckx
Copyright © 2012 Bernd Porr
Copyright © 2012 Ian Abbott
Copyright © 2012, 2015 Éric Piel

This document is part of Comedilib. In the context of this document, the term "source code" as defined by the license is interpreted as the XML source.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, version 2.1 of the License.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

12/30/2018 Comedi