1COMEDI_GET_SOFTCAL_CONVERTER(3) COMEDI_GET_SOFTCAL_CONVERTER(3)
2
6 comedi_get_softcal_converter - get converter for software-calibrated
7 subdevice
8
10 #include <comedilib.h>
11 int comedi_get_softcal_converter (unsigned subdevice, unsigned channel,
13 unsigned range, enum comedi_conversion_direction direction, const
14 comedi_calibration_t *parsed_calibration, comedi_polynomial_t *con‐
15 verter);
16
18 alpha
19
21 comedi_get_softcal_converter() initializes converter so it can be
22 passed to either comedi_to_physical() or comedi_from_physical(). The
23 converter parameter can then be used to convert data from the specified
24 subdevice, channel, and range. The direction parameter specifies
25 whether converter will be passed to comedi_to_physical() or
26 comedi_from_physical(). The parsed_calibration parameter contains the
27 software calibration values for your device, and may be obtained by
28 calling comedi_parse_calibration_file() on a calibration file generated
29 by the comedi_soft_calibrate program.
30 This function is only useful for boards that perform their calibrations
32 in software on the host computer. A subdevice will advertise the fact
33 that it depends on a software calibration with the SDF_SOFT_CALIBRATED
34 subdevice flag.
35 Whether or not the result of this function actually depends on the
37 channel parameter is hardware dependent. For example, a multiplexed
38 analog input will typically use the same calibration for all input
39 channels. Analog outputs will typically use different calibrations for
40 each output channel.
41 Software calibrations are implemented as polynomials (up to third
43 order). Since the inverse of polynomials of order higher than one
44 can't be represented exactly as another polynomial, you may not be able
45 to get converters for the "reverse" direction. For example, you may be
46 able to get a converter for an analog input in the COMEDI_TO_PHYSICAL
47 direction, but not in the COMEDI_FROM_PHYSICAL direction.
48
50 Zero on success or -1 on failure.
51 28 October 2007COMEDI_GET_SOFTCAL_CONVERTER(3)