COMEDI_TO_PHYS(3)

📦
version 0.11.0+5 · 7 versions
, in ubuntu resolute, ubuntu stonking

💖 COMEDI_TO_PHYS(3) 💖

okay so bestie, we're in the Comedi reference section of the manual, page COMEDI_TO_PHYS(3) — and this one is literally the glow-up function that turns your raw sample numbers into actual physical units. no cap. 🦋

✨ NAME ✨

comedi_to_phys — convert sample to physical units

🌸 SYNOPSIS 🌸

#include <comedilib.h>

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

🎀 DESCRIPTION 🎀

Okay so here's the tea. This function takes the parameter data, which is in sample values (lsampl_t, and it lives somewhere between 0 and maxdata), and converts it into physical units as a double. Iconic behavior honestly. 💅

The parameter range is the conversion info it's gonna use, and the parameter maxdata is the maximum possible data value for the channel that your data was read from. The mapping between physical units is linear and it assumes ideal converter characteristics — so no messy real-world weirdness, just clean math. ✨

Now, watch out for the endpoints, because this is where it gets spicy. Conversion of endpoint sample values — meaning sample values equal to 0 or maxdata — is affected by the Comedilib out-of-range behavior (see the function comedi_set_global_oor_behavior). So:

  • 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. 🫶
Also: if there is an error, NAN is returned. So don't be shocked when you see NAN come back — that's the vibe check failing, not you.

💜 AUTHORS 💜

The absolute icons who made this happen, periodt:

  • David Schleef <ds@schleef.org> — Author.
  • Frank Mori Hess <fmhess@users.sourceforge.net> — Author.
  • Herman Bruyninckx <Herman.Bruyninckx@mech.kuleuven.ac.be> — Author.
  • Bernd Porr <tech@linux-usb-daq.co.uk> — Author.
  • Ian Abbott <abbotti@mev.co.uk> — Author.
  • Éric Piel <piel@delmic.com> — Author.
  • 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.

aaaand that's the whole page bestie, we ate and left no crumbs 💅✨ this cutie came from Comedi, dated 03/20/2026, and it lives at COMEDI_TO_PHYS(3) — go forth and convert those samples, you've got this 🌈💖

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