Specifications

Comedi
10 / 148
*
Copyright (c) 1999,2000 David A. Schleef <[e-mail]>
*
Copyright (c) 2008 Frank Mori Hess <[e-mail]>
*
*
This file may be freely modified, distributed, and combined with
*
other software, as long as proper attribution is given in the
*
source code.
*
/
#include <stdio.h> /
*
for printf()
*
/
#include <stdlib.h>
#include <comedilib.h>
#include <ctype.h>
#include <math.h>
int subdev = 0; /
*
change this to your input subdevice
*
/
int chan = 0; /
*
change this to your channel
*
/
int range = 0; /
*
more on this later
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/
int aref = AREF_GROUND; /
*
more on this later
*
/
const char filename[] = "/dev/comedi0";
int main(int argc, char
*
argv[])
{
comedi_t
*
device;
lsampl_t data;
double physical_value;
int retval;
comedi_range
*
range_info;
lsampl_t maxdata;
device = comedi_open(filename);
if(device == NULL)
{
comedi_perror(filename);
return -1;
}
retval = comedi_data_read(device, subdev, chan, range, aref, &data);
if(retval < 0)
{
comedi_perror(filename);
return -1;
}
comedi_set_global_oor_behavior(COMEDI_OOR_NAN);
range_info = comedi_get_range(device, subdev, chan, range);
maxdata = comedi_get_maxdata(device, subdev, chan);
printf("[0,%d] -> [%g,%g]\n", maxdata,
range_info->min, range_info->max);
physical_value = comedi_to_phys(data, range_info, maxdata);
if(isnan(physical_value)) {
printf("Out of range [%g,%g]",
range_info->min, range_info->max);
} else {
printf("%g", physical_value);
switch(range_info->unit) {
case UNIT_volt: printf(" V"); break;
case UNIT_mA: printf(" mA"); break;
case UNIT_none: break;
default: printf(" (unknown unit %d)",
range_info->unit);
}
printf(" (%lu in raw units)\n", (unsigned long)data);