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amplifier.c

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/*
   amplifier.c

   C defs for amplifier code

   Modification history:

   14-Apr-2000 WPS added _attribute__((unused)) to ident
   23-Sep-1999  WPS replaced stdio functions with inet_file functions
   which work under CE.
   17-Mar-1998  FMP added section arg to amplifierIniLoad()
   24-Apr-1997  FMP added amplifierIniLoad()
   17-Apr-1997  FMP created from C portion of original amplifier.c
*/

#ifndef NO_STDIO_SUPPORT
#ifndef UNDER_CE
#include <stdio.h>
#include <string.h>
#endif
#include "inetfile.hh"          /* inet_file_open() */
#include "inifile.h"
#include "rcs_prnt.hh"          /* rcs_print() */
#endif
#include <math.h>               /* fabs() */
#include "amplifier.h"          /* these decls */

/* ident tag */
#ifndef __GNUC__
#ifndef __attribute__
#define __attribute__(x)
#endif
#endif

static char __attribute__((unused)) ident[] = "$Id: amplifier.c,v 1.2 2000/10/27 20:34:42 terrylr Exp $";

#define GAIN_SET 0x01
#define MAX_OUTPUT_CURRENT_SET 0x02
#define LOAD_RESISTANCE_SET 0x04
#define ALL_SET (GAIN_SET | MAX_OUTPUT_CURRENT_SET | LOAD_RESISTANCE_SET)

int amplifierInit(AMPLIFIER_STRUCT * amp)
{
  /* parameters */
  if (0 == amp)
  {
    return -1;
  }

  amp->gain = 0.0;
  amp->maxOutputCurrent = 0.0;
  amp->loadResistance = 1.0;    /* not zero-- it's a denominator */

  /* internal vars */
  amp->configured = 0;
  amp->enabled = 0;
  amp->tripped = 0;

  return 0;
}

int amplifierSetGain(AMPLIFIER_STRUCT * amp, double gain)
{
  if (0 == amp ||
      gain <= 0.0)
  {
    return -1;
  }

  amp->gain = gain;
  amp->configured |= GAIN_SET;

  return 0;
}

double amplifierGetGain(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp ||
      ! (amp->configured & GAIN_SET))
  {
    return 0.0;
  }

  return amp->gain;
}

int amplifierSetMaxOutputCurrent(AMPLIFIER_STRUCT * amp,
                                 double maxOutputCurrent)
{
  if (0 == amp ||
      maxOutputCurrent <= 0.0)
  {
    return -1;
  }

  amp->maxOutputCurrent = maxOutputCurrent;
  amp->configured |= MAX_OUTPUT_CURRENT_SET;

  return 0;
}

double amplifierGetMaxOutputCurrent(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp ||
      ! (amp->configured & MAX_OUTPUT_CURRENT_SET))
  {
    return 0.0;
  }

  return amp->maxOutputCurrent;
}

int amplifierSetLoadResistance(AMPLIFIER_STRUCT * amp, double loadResistance)
{
  if (0 == amp ||
      loadResistance <= 0.0)
  {
    return -1;
  }

  amp->loadResistance = loadResistance;
  amp->configured |= LOAD_RESISTANCE_SET;

  return 0;
}

double amplifierGetLoadResistance(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp ||
      ! (amp->configured & LOAD_RESISTANCE_SET))
  {
    return 0.0;
  }

  return amp->loadResistance;
}

/* enables output */
int amplifierEnable(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp)
  {
    return -1;
  }

  if (! amp->tripped &&
      amp->configured == ALL_SET)
  {
    amp->enabled = 1;
  }

  return 0;
}

/* disabled output */
int amplifierDisable(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp)
  {
    return -1;
  }

  amp->enabled = 0;

  return 0;
}

/* 0 = disabled; non-zero = enabled, -1 == error */
int amplifierIsEnabled(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp)
  {
    return -1;
  }

  return amp->enabled;
}

/* resets trip condition */
int amplifierReset(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp)
  {
    return -1;
  }

  if (amp->configured == ALL_SET)
  {
    amp->enabled = 0;
    amp->tripped = 0;
  }

  return 0;
}

/* 0 = not tripped; non-zero = tripped, -1 == error */
int amplifierIsTripped(AMPLIFIER_STRUCT * amp)
{
  if (0 == amp)
  {
    return -1;
  }

  return amp->tripped;
}

double amplifierRunCycle(AMPLIFIER_STRUCT * amp, double input)
{
  double output;
  double outputCurrent;

  /* check for configured */
  if (0 == amp ||
      amp->configured != ALL_SET)
  {
    return 0.0;
  }

  /* check state for allowing output */
  if (! amp->enabled ||
      amp->tripped)
  {
    return 0.0;                 /* disabled-- hold output at 0.0 */
  }

  /* finally-- do the simple math */
  output = amp->gain * input;
  outputCurrent = fabs(output / amp->loadResistance);

  /* check output */
  if (outputCurrent > amp->maxOutputCurrent)
  {
    amp->tripped = 1;
    amp->enabled = 0;
    output = 0.0;
  }

  return output;
}

int amplifierIniLoad(AMPLIFIER_STRUCT * amplifier, const char * filename, const char *section)
{
#ifndef NO_STDIO_SUPPORT

  AMPLIFIER_STRUCT amp;
  int retval = 0;
  const char *inistring;

#ifndef UNDER_CE
  FILE *fp;

  if (NULL == (fp = fopen(filename, "r")))
  {
    rcs_print_error( "can't open ini file %s\n", filename);
    return -1;
  }
#else
  INET_FILE *fp;

  if (NULL == (fp = inet_file_open(filename, "r")))
  {
    rcs_print_error( "can't open ini file %s\n", filename);
    return -1;
  }
#endif

  memset(&amp,0,sizeof(amp));
  if (NULL != (inistring = iniFind(fp, "AMPLIFIER_GAIN", section)))
  {
#ifndef UNDER_CE
    if (1 != sscanf((char *) inistring, "%lf", &amp.gain))
    {
      /* found, but invalid */
      rcs_print_error( "invalid GAIN: %s\n", inistring);
      retval = -1;
    }
    else
    {
      amplifierSetGain(amplifier, amp.gain);
    }
#else
    amp.gain = RCS_CE_ATOF(inistring);
    amplifierSetGain(amplifier, amp.gain);
#endif
  }

  if (NULL != (inistring = iniFind(fp, "MAX_OUTPUT_CURRENT", section)))
  {
#ifndef UNDER_CE
    if (1 != sscanf((char *) inistring, "%lf", &amp.maxOutputCurrent))
    {
      /* found, but invalid */
      rcs_print_error( "invalid MAX_OUTPUT_CURRENT: %s\n", inistring);
      retval = -1;
    }
    else
    {
      amplifierSetMaxOutputCurrent(amplifier, amp.maxOutputCurrent);
    }
#else
    amp.maxOutputCurrent =  RCS_CE_ATOF(inistring);
    amplifierSetMaxOutputCurrent(amplifier, amp.maxOutputCurrent);
#endif
  }

  if (NULL != (inistring = iniFind(fp, "LOAD_RESISTANCE", section)))
  {
#ifndef UNDER_CE
    if (1 != sscanf((char *) inistring, "%lf", &amp.loadResistance))
    {
      /* found, but invalid */
      rcs_print_error( "invalid LOAD_RESISTANCE: %s\n", inistring);
      retval = -1;
    }
    else
    {
      amplifierSetLoadResistance(amplifier, amp.loadResistance);
    }
#else
    amp.loadResistance =  RCS_CE_ATOF(inistring);
    amplifierSetLoadResistance(amplifier, amp.loadResistance);
#endif
  }

  /* close inifile */
#ifndef UNDER_CE
  fclose(fp);
#else
  inet_file_close(fp);
#endif


  return retval;

#else

  return -1;

#endif
}

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