linuxcnc-hal-sys 0.1.5

/*
  vfdb_vfd.c

  userspace HAL program to control a Delta VFD-B VFD

  Yishin Li, adapted from Michael Haberler's vfs11_vfd/.

  Copyright (C) 2007, 2008 Stephen Wille Padnos, Thoth Systems, Inc.
  Copyright (C) 2009 John Thornton
  Copyright (C) 2009,2010,2011,2012 Michael Haberler
  Copyright (C) 2013 Yishin Li
  Copyright (C) 2013 Sebastian Kuzminsky

  Based on a work (test-modbus program, part of libmodbus) which is
  Copyright (C) 2001-2005 Stéphane Raimbault <stephane.raimbault@free.fr>

  This program 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.

  This program 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
  General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301-1307  USA.

  see 'man vfdb_vfd' and the VFD-B section in the Drivers manual.

 */


#ifndef ULAPI
#error This is intended as a userspace component only.
#endif

#ifdef DEBUG
#define DBG(fmt, ...)					\
        do {						\
            if (param.debug) printf(fmt,  ## __VA_ARGS__);	\
        } while(0)
#else
#define DBG(fmt, ...)
#endif

#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <getopt.h>
#include <math.h>
#include <signal.h>
#include <stdarg.h>

#include "rtapi.h"
#include "hal.h"
#include <modbus.h>
#include <modbus-tcp.h>
#include "inifile.h"

// command registers for DELTA VFD-B Inverter
#define REG_COMMAND1                    0x2000  // "Communication command" - start/stop, fwd/reverse, DC break, fault reset, panel override
#define REG_FREQUENCY                   0x2001  // Set frequency in 0.01Hz steps
#define REG_UPPERLIMIT                  0x0100  // limit on output frequency in VFD

// command bits
#define CMD_FAULT_RESET		0x2000
#define CMD_EMERGENCY_STOP	0x1000
#define CMD_RUN			0x0002
#define CMD_STOP                0x0001
#define CMD_REVERSE		0x0020
#define CMD_FORWARD             0x0010
#define CMD_JOG_RUN		0x0003

// status registers for DELTA VFD-B Inverter
#define SR_ERROR_CODE           0x2100                  //
#define SR_INV_OPSTATUS         0x2101                   //
#define SR_OUTPUT_FREQ          0x2103                   // 0.01Hz units
#define ST_EMERGENCY_STOPPED    0x0021          // EF1/ESTOP

#define SR_MOTOR_SPEED          0x210C          // RPM
#define SR_TORQUE_RATIO         0x210B          // %
#define SR_OUTPUT_CURRENT       0x2104          // output curr
#define SR_OUTPUT_VOLTAGE       0x2106          // %
#define SR_INVERTER_MODEL	0x0000
#define SR_RATED_CURRENT	0x0001		// 0.1A
#define SR_RATED_VOLTAGE	0x0102		// 0.1V
#define SR_EEPROM_VERSION	0x0006

/* There's an assumption in the gs2_vfd code, namely that the interesting registers
 * are contiguous and all of them can be read with a single read_holding_registers()
 * operation.
 *
 * However, the interesting VFD-B registers are not contiguous, and must be read
 * one-by-one, because the Toshiba Modbus implementation only supports single-value
 * modbus_read_registers() queries, slowing things down considerably. It seems that
 * other VFD's have similar restrictions.
 *
 * Then, not all registers are equally important. We would like to read the
 * VFD status and actual frequency on every Modbus turnaround, but there is no need to
 * the read CPU version and inverter model more than once at startup, and the load factor etc 
 * every so often. 
 */
#define POLLCYCLES 	10      // read less important parameters only on every 10th transaction
#define MODBUS_MIN_OK	10      // assert the modbus-ok pin after 10 successful modbus transactions


/* HAL data struct */
typedef struct {
    hal_s32_t   *error_code;
    hal_s32_t 	*status;
    hal_float_t	*freq_cmd;	// frequency command
    hal_float_t	*freq_out;	// actual output frequency
    hal_float_t	*output_volt;	// output voltage
    hal_float_t	*RPM;
    hal_float_t *RPS;
    hal_float_t	*torque_ratio;
    hal_float_t	*output_current;
    hal_float_t *max_rpm;	// calculated based on VFD max frequency setup parameter
    hal_bit_t	*at_speed;	// when drive freq_cmd == freq_out and running
    hal_bit_t	*is_stopped;	// when drive freq out is 0
    hal_bit_t	*is_e_stopped;	// true if emergency stop status set in 0xFD00
    hal_bit_t	*modbus_ok;	// the last MODBUS_OK transactions returned successfully
    hal_float_t	*speed_command;	// speed command input

    hal_bit_t	*spindle_on;	// spindle 1=on, 0=off
    // hal_bit_t	*err_reset;	// reset errors when 1  - set fault reset bit in 0xFA00
    hal_bit_t	*jog_mode;	// termed 'jog-run' in manual - might be useful for spindle positioning
    hal_s32_t	*errorcount;    // number of failed Modbus transactions - hints at logical errors

    hal_float_t	looptime;
    hal_float_t	speed_tolerance; 	
    hal_float_t	motor_nameplate_hz;	// speeds are scaled in Hz, not RPM
    hal_float_t	motor_nameplate_RPM;	// nameplate RPM at default Hz
    hal_float_t	rpm_limit;		// do-not-exceed output frequency
    hal_bit_t	*enabled;		// if set: control VFD via Modbus commands, panel control disabled
    // if zero (default): manual control through panel enabled
    hal_float_t	*upper_limit_hz;		// VFD setup parameter - maximum output frequency in HZ

    hal_bit_t   *max_speed;             // 1: run as fast as possible, ignore unimportant registers
    // link this to spindle.orient-enable for better orient PID loop behaviour
} haldata_t;

// configuration and execution state
typedef struct params {
    char *modname;
    int modbus_debug;
    int debug;
    int slave;
    int pollcycles; 
    char *device;
    int baud;
    int bits;
    char parity;
    int stopbits;
    char *progname;
    char *section;
    FILE *fp;
    char *inifile;
    int reconnect_delay;
    modbus_t *ctx;
    haldata_t *haldata;
    int hal_comp_id;
    int read_initial_done;
    // int old_err_reset;
    uint16_t old_cmd1_reg;		// copy of last write to FA00 */
    int modbus_ok;
    uint16_t failed_reg;		// remember register for failed modbus transaction for debugging
    int	last_errno;
    int report_device;
    int motor_hz;  // rated frequency of the motor
    int motor_rpm;  // rated speed of the motor
} params_type, *param_pointer;

// default options; read from inifile or command line
static params_type param = {
        .modname = NULL,
        .modbus_debug = 0,
        .debug = 0,
        .slave = 1,
        .pollcycles = POLLCYCLES,
        .device = "/dev/ttyS0",
        .baud = 19200,
        .bits = 8,
        .parity = 'E',
        .stopbits = 1,
        .progname = "vfdb_vfd",
        .section = "VFD-B",
        .fp = NULL,
        .inifile = NULL,
        .reconnect_delay = 1,
        .ctx = NULL,
        .haldata = NULL,
        .hal_comp_id = -1,
        .read_initial_done = 0,
        // .old_err_reset = 0,
        .old_cmd1_reg = 0,
        .modbus_ok = 0,    // set modbus-ok bit if last MODBUS_OK transactions went well
        .failed_reg =0,
        .last_errno = 0,
        .report_device = 0,
        .motor_hz = 50,     // 50 is common in Europe, 60 is common in the US
        .motor_rpm = 1410,  // 1410 is common in Europe, 1730 is common in the US
};


static int connection_state;
enum connstate {NOT_CONNECTED, OPENING, CONNECTING, CONNECTED, RECOVER, DONE};

static char *option_string = "dhrmn:S:I:";
static struct option long_options[] = {
        {"debug", no_argument, 0, 'd'},
        {"help", no_argument, 0, 'h'},
        {"modbus-debug", no_argument, 0, 'm'},
        {"report-device", no_argument, 0, 'r'},
        {"ini", required_argument, 0, 'I'},     // default: getenv(INI_FILE_NAME)
        {"section", required_argument, 0, 'S'}, // default section = LIBMODBUS
        {"name", required_argument, 0, 'n'},    // vfd-b
        {0,0,0,0}
};


void  windup(param_pointer p) 
{
    if (p->haldata && *(p->haldata->errorcount)) {
        fprintf(stderr,"%s: %d modbus errors\n",p->progname, *(p->haldata->errorcount));
        fprintf(stderr,"%s: last command register: 0x%.4x\n",p->progname, p->failed_reg);
        fprintf(stderr,"%s: last error: %s\n",p->progname, modbus_strerror(p->last_errno));
    }
    if (p->hal_comp_id >= 0)
        hal_exit(p->hal_comp_id);
    if (p->ctx)
        modbus_close(p->ctx);
}

static void toggle_modbus_debug(int sig)
{
    param.modbus_debug = !param.modbus_debug;
    modbus_set_debug(param.ctx, param.modbus_debug);
}

static void toggle_debug(int sig)
{
    param.debug = !param.debug;
}

static void quit(int sig) 
{
    if (param.debug)
        fprintf(stderr,"quit(connection_state=%d)\n",connection_state);

    switch (connection_state) {

    case CONNECTING:  
        // modbus_tcp_accept() or TCP modbus_connect()  were interrupted
        // these wont return to the main loop, so exit here
        windup(&param);
        exit(0);
        break;

    default:
        connection_state = DONE;
        break;
    }
}

enum kwdresult {NAME_NOT_FOUND, KEYWORD_INVALID, KEYWORD_FOUND};
#define MAX_KWD 10

int findkwd(param_pointer p, const char *name, int *result, const char *keyword, int value, ...)
{
    const char *word;
    va_list ap;
    const char *kwds[MAX_KWD], **s;
    int nargs = 0;

    if ((word = iniFind(p->fp, name, p->section)) == NULL)
        return NAME_NOT_FOUND;

    kwds[nargs++] = keyword;
    va_start(ap, value);

    while (keyword != NULL) {
        if (!strcasecmp(word, keyword)) {
            *result = value;
            va_end(ap);
            return KEYWORD_FOUND;
        }
        keyword = va_arg(ap, const char *);
        kwds[nargs++] = keyword;
        if (keyword)
            value = va_arg(ap, int);
    }  
    fprintf(stderr, "%s: %s:[%s]%s: found '%s' - not one of: ", 
            p->progname, p->inifile, p->section, name, word);
    for (s = kwds; *s; s++) 
        fprintf(stderr, "%s ", *s);
    fprintf(stderr, "\n");
    va_end(ap);
    return KEYWORD_INVALID;
}

int read_ini(param_pointer p)
{
    const char *s;
    int value;

    if ((p->fp = fopen(p->inifile,"r")) != NULL) {
        if (!p->debug)
            iniFindInt(p->fp, "DEBUG", p->section, &p->debug);
        if (!p->modbus_debug)
            iniFindInt(p->fp, "MODBUS_DEBUG", p->section, &p->modbus_debug);
        iniFindInt(p->fp, "BITS", p->section, &p->bits);
        iniFindInt(p->fp, "BAUD", p->section, &p->baud);
        iniFindInt(p->fp, "STOPBITS", p->section, &p->stopbits);
        iniFindInt(p->fp, "TARGET", p->section, &p->slave);
        iniFindInt(p->fp, "POLLCYCLES", p->section, &p->pollcycles);
        iniFindInt(p->fp, "RECONNECT_DELAY", p->section, &p->reconnect_delay);

        iniFindInt(p->fp, "MOTOR_HZ", p->section, &p->motor_hz);
        iniFindInt(p->fp, "MOTOR_RPM", p->section, &p->motor_rpm);

        if ((s = iniFind(p->fp, "DEVICE", p->section))) {
            p->device = strdup(s);
        }
        value = p->parity;
        if (findkwd(p, "PARITY", &value,
                "even",'E',
                "odd", 'O',
                "none", 'N',
                NULL) == KEYWORD_INVALID)
            return -1;
        p->parity = value;
    } else {
        fprintf(stderr, "%s:cant open inifile '%s'\n",
                p->progname, p->inifile);
        return -1;
    }
    return 0;
}

void usage(int argc, char **argv) {
    printf("Usage:  %s [options]\n", argv[0]);
    printf("This is a userspace HAL program, typically loaded using the halcmd \"loadusr\" command:\n"
            "    loadusr vfdb_vfd [options]\n"
            "Options are:\n"
            "-I or --ini <inifile>\n"
            "    Use <inifile> (default: take ini filename from environment variable INI_FILE_NAME)\n"
            "-S or --section <section-name> (default 8)\n"
            "    Read parameters from <section_name> (default 'VFD-B')\n"
            "-d or --debug\n"
            "    Turn on debugging messages. Toggled by USR1 signal.\n"
            "-m or --modbus-debug\n"
            "    Turn on modbus debugging.  This will cause all modbus messages\n"
            "    to be printed in hex on the terminal. Toggled by USR2 signal.\n"
            "-r or --report-device\n"
            "    Report device properties on console at startup\n");
}

int write_data(modbus_t *ctx, haldata_t *haldata, param_pointer p)
{
    hal_float_t hzcalc;
    int cmd1_reg;
    int freq_reg, freq_cap;

    if (!*(haldata->enabled)) {
        // send 0 to 0x2000 register - no bus control
        if (modbus_write_register(ctx, REG_COMMAND1, 0) < 0) {
            p->failed_reg = REG_COMMAND1;
            (*haldata->errorcount)++;
            p->last_errno = errno;
            return errno;
        }
        return 0;
    }

retry:
    // set frequency register
    hzcalc = haldata->motor_nameplate_hz / haldata->motor_nameplate_RPM;
    freq_reg =  (int)round(fabs((*(haldata->speed_command) * hzcalc * 100.0)));
    freq_cap =  (int)round(fabs((haldata->rpm_limit * hzcalc * 100)));

    // limit frequency to frequency set via max-rpm
    if (freq_reg > freq_cap)
        freq_reg = freq_cap;

    *(haldata->freq_cmd)  =  freq_reg / 100.0;

    // prepare command register
    cmd1_reg = 0;
    if (*haldata->spindle_on){
        cmd1_reg |= (*haldata->jog_mode) ? CMD_JOG_RUN : CMD_RUN;
    } else {
        cmd1_reg |= CMD_STOP;
    }

    if (*(haldata->speed_command) >= 0) {
        cmd1_reg |= CMD_FORWARD;
    } else {
        cmd1_reg |= CMD_REVERSE;
    }

//TODO: implement RESET command for VFD-B
//    // send CMD_FAULT_RESET and CMD_EMERGENCY_STOP only once so the poor thing comes back
//    // out of reset/estop status eventually
//    if (*(haldata->err_reset) && !(p->old_cmd1_reg  & CMD_FAULT_RESET ))	{ // not sent yet
//        cmd1_reg |= CMD_FAULT_RESET;		// fault reset bit = 1 -> clear fault
//        *(haldata->err_reset) = 0;
//    } else {
//        cmd1_reg &= ~CMD_FAULT_RESET;
//    }

    DBG("write_data: cmd1_reg=0x%4.4X old cmd1_reg=0x%4.4X\n", cmd1_reg,p->old_cmd1_reg);

    if (modbus_write_register(ctx, REG_COMMAND1, cmd1_reg) < 0) {
        // modbus transaction timed out. This may happen if VFD is in E-Stop.
        // if VFD was in E-Stop, and a fault reset was sent, wait about 2 seconds for recovery
        // we must assume that any command and frequency values sent were cleared, so we restart
        // the operation.
        // note that sending the CMD_EMERGENCY_STOP bit in cmd1_reg causes an immediate reboot
        // without a Modbus reply (if the VFD actually was in e-stop) so we ignore this error.
        if (cmd1_reg & CMD_EMERGENCY_STOP) {
            sleep(2);
            goto retry;
        }
        p->failed_reg = REG_COMMAND1;
        (*haldata->errorcount)++;
        p->last_errno = errno;
        return errno;
    } 

    // remember so we can toggle fault/estop reset just once
    // otherwise the VFD keeps rebooting as long as the fault reset/estop reset bits are sent
    p->old_cmd1_reg = cmd1_reg;

    if ((modbus_write_register(ctx, REG_FREQUENCY, freq_reg)) < 0) {
        p->failed_reg = REG_FREQUENCY;
        (*haldata->errorcount)++;
        p->last_errno = errno;
        return errno;
    } 

    return 0;
}

#define GETREG(reg,into)					\
        do {							\
            curr_reg = reg;						\
            if (modbus_read_registers(ctx, reg, 1, into) != 1)	\
            goto failed;					\
        } while (0)


int read_initial(modbus_t *ctx, haldata_t *haldata, param_pointer p)
{
    uint16_t curr_reg, current, 
    voltage, model, eeprom, max_freq;

    GETREG(REG_UPPERLIMIT, &max_freq);
    *(haldata->upper_limit_hz) = (float)max_freq/100.0;
    *(haldata->max_rpm) = *(haldata->upper_limit_hz) * 
            haldata->motor_nameplate_RPM / haldata->motor_nameplate_hz;

    if (p->report_device) {
        GETREG(SR_RATED_CURRENT, &current);
        GETREG(SR_RATED_VOLTAGE, &voltage);
        GETREG(SR_INVERTER_MODEL, &model);
        GETREG(SR_EEPROM_VERSION, &eeprom);

        printf("%s: inverter model: %d/0x%4.4x\n",
                p->progname, model, model);
        printf("%s: maximum ratings: %.1fV %.1fA %.2fHz\n",
                p->progname, voltage/10.0, current/10.0, max_freq/100.0);
        printf("%s: versions: eeprom=%d/0x%4.4x\n",
                p->progname, eeprom, eeprom);
    }
    return 0;

    failed:
    p->failed_reg = curr_reg;
    p->last_errno = errno;
    (*haldata->errorcount)++;
    if (p->debug)
        fprintf(stderr, "%s: read_initial: modbus_read_registers(0x%4.4x): %s\n",
                p->progname, curr_reg, modbus_strerror(errno));
    return p->last_errno;
}

int read_data(modbus_t *ctx, haldata_t *haldata, param_pointer p)
{
    int retval;
    uint16_t curr_reg, val, status_reg, freq_reg;
    static int pollcount = 0;

    if (!p->read_initial_done) {
        if ((retval = read_initial(ctx, haldata, p)))
            return retval;
        else
            p->read_initial_done = 1;
    }

    GETREG(SR_ERROR_CODE, &curr_reg);
    *(haldata->error_code) = curr_reg;

    // we always at least read the main status register SR_INV_OPSTATUS
    // and current operating frequency SR_OP_FREQUENCY
    GETREG(SR_INV_OPSTATUS, &status_reg);
    *(haldata->status) = status_reg;

    GETREG(SR_OUTPUT_FREQ, &freq_reg);
    *(haldata->freq_out) = freq_reg * 0.01;

    DBG("read_data: status_reg=%4.4x freq_reg=%4.4x\n", status_reg, freq_reg);

    // JET if freq out is 0 then the drive is stopped
    *(haldata->is_stopped) = (freq_reg == 0);

    if (status_reg == ST_EMERGENCY_STOPPED) {	// set e-stop status.
        *(haldata->is_e_stopped) = 1;
    } else {
        *(haldata->is_e_stopped) = 0;
    }

    if ((pollcount == 0) && !*(haldata->max_speed)) {
        // less urgent registers
        GETREG(SR_MOTOR_SPEED, &val);
        *(haldata->RPM) = val;
        *(haldata->RPS) = val/60.0;

        GETREG(SR_TORQUE_RATIO, &val);
        *(haldata->torque_ratio) =  val;

        GETREG(SR_OUTPUT_CURRENT, &val);
        *(haldata->output_current) =  val * 0.1;

        GETREG(SR_OUTPUT_VOLTAGE, &val);
        *(haldata->output_volt) =  val * 0.1;

        {
            float speed_error;
            speed_error = (*haldata->RPM / *haldata->speed_command) - 1.0;
            if (fabs(speed_error) > haldata->speed_tolerance) {
                *haldata->at_speed = 0;
            } else {
                *haldata->at_speed = 1;
            }
        }
    } else {
        pollcount++;
    }

    if (pollcount >= p->pollcycles)
        pollcount = 0;

    p->last_errno = retval = 0;
    return 0;

    failed:
    p->failed_reg = curr_reg;
    p->last_errno = errno;
    (*haldata->errorcount)++;
    if (p->debug)
        fprintf(stderr, "%s: read_data: modbus_read_registers(0x%4.4x): %s\n",
                p->progname, curr_reg, modbus_strerror(errno));
    return p->last_errno;
}

#undef GETREG

#define PIN(x)					\
        do {						\
            status = (x);					\
            if ((status) != 0)				\
            return status;				\
        } while (0)

int hal_setup(int id, haldata_t *h, const char *name)
{
    int status;
    PIN(hal_pin_bit_newf(HAL_OUT, &(h->at_speed), id, "%s.at-speed", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->output_current), id, "%s.output-current", name));
    PIN(hal_pin_bit_newf(HAL_IN, &(h->enabled), id, "%s.enable", name));
    // PIN(hal_pin_bit_newf(HAL_IN, &(h->err_reset), id, "%s.err-reset", name));
    PIN(hal_pin_bit_newf(HAL_IN, &(h->jog_mode), id, "%s.jog-mode", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->freq_cmd), id, "%s.frequency-command", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->freq_out), id, "%s.frequency-out", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->torque_ratio), id, "%s.inverter-load-percentage", name));
    PIN(hal_pin_bit_newf(HAL_OUT, &(h->is_e_stopped), id, "%s.is-e-stopped", name)); // JET
    PIN(hal_pin_bit_newf(HAL_OUT, &(h->is_stopped), id, "%s.is-stopped", name)); // JET
    PIN(hal_pin_float_newf(HAL_OUT, &(h->max_rpm), id, "%s.max-rpm", name));
    PIN(hal_pin_bit_newf(HAL_OUT, &(h->modbus_ok), id, "%s.modbus-ok", name)); // JET
    PIN(hal_pin_float_newf(HAL_OUT, &(h->RPM), id, "%s.motor-RPM", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->RPS), id, "%s.motor-RPS", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->output_volt), id, "%s.output-voltage", name));
    PIN(hal_pin_float_newf(HAL_IN, &(h->speed_command), id, "%s.speed-command", name));
    PIN(hal_pin_bit_newf(HAL_IN, &(h->spindle_on), id, "%s.spindle-on", name));
    PIN(hal_pin_s32_newf(HAL_OUT, &(h->error_code), id, "%s.error-code", name));
    PIN(hal_pin_s32_newf(HAL_OUT, &(h->status), id, "%s.status", name));
    PIN(hal_pin_bit_newf(HAL_IN, &(h->max_speed), id, "%s.max-speed", name));
    PIN(hal_pin_s32_newf(HAL_OUT, &(h->errorcount), id, "%s.error-count", name));
    PIN(hal_pin_float_newf(HAL_OUT, &(h->upper_limit_hz), id, "%s.frequency-limit", name));

    PIN(hal_param_float_newf(HAL_RW, &(h->looptime), id, "%s.loop-time", name));
    PIN(hal_param_float_newf(HAL_RW, &(h->motor_nameplate_hz), id, "%s.nameplate-HZ", name));
    PIN(hal_param_float_newf(HAL_RW, &(h->motor_nameplate_RPM), id, "%s.nameplate-RPM", name));
    PIN(hal_param_float_newf(HAL_RW, &(h->rpm_limit), id, "%s.rpm-limit", name));
    PIN(hal_param_float_newf(HAL_RW, &(h->speed_tolerance), id, "%s.tolerance", name));

    return 0;
}
#undef PIN

int set_defaults(param_pointer p)
{
    haldata_t *h = p->haldata;

    *(h->status) = 0;
    *(h->freq_cmd) = 0;
    *(h->freq_out) = 0;
    *(h->output_volt) = 0;
    *(h->RPM) = 0;
    *(h->torque_ratio) = 0;
    *(h->output_current) = 0;
    *(h->upper_limit_hz) = 0;
    *(h->at_speed) = 0;
    *(h->is_stopped) = 0;
    *(h->is_e_stopped) = 0;
    *(h->speed_command) = 0;
    *(h->modbus_ok) = 0;

    *(h->spindle_on) = 0;
    // *(h->err_reset) = 0;
    *(h->jog_mode) = 0;
    *(h->enabled) = 0;
    *(h->errorcount) = 0;
    *(h->max_speed) = 0;

    h->looptime = 0.1;
    h->speed_tolerance = 0.01;      // output frequency within 1% of target frequency
    h->motor_nameplate_hz = p->motor_hz;
    h->motor_nameplate_RPM = p->motor_rpm;
    h->rpm_limit = p->motor_rpm;

    p->failed_reg = 0;
    return 0;
}

int main(int argc, char **argv)
{
    struct timespec loop_timespec, remaining;
    int opt;
    param_pointer p = &param;
    int retval = -1;

    p->progname = argv[0];
    connection_state = NOT_CONNECTED;
    p->inifile = getenv("INI_FILE_NAME");

    while ((opt = getopt_long(argc, argv, option_string, long_options, NULL)) != -1) {
        switch(opt) {
        case 'n':
            p->modname = strdup(optarg);
            break;
        case 'm':
            p->modbus_debug = 1;
            break;
        case 'd':
            p->debug = 1;
            break;
        case 'S':
            p->section = optarg;
            break;
        case 'I':
            p->inifile = optarg;
            break;
        case 'r':
            p->report_device = 1;
            break;
        case 'h':
        default:
            usage(argc, argv);
            exit(0);
        }
    }

    if (p->inifile) {
        if (read_ini(p))
            goto finish;
        if (!p->modname)
            p->modname = "vfdb_vfd";
    } else {
        fprintf(stderr, "%s: ERROR: no inifile - either use '--ini inifile' or set INI_FILE_NAME environment variable\n", p->progname);
        goto finish;
    }

    signal(SIGINT, quit);
    signal(SIGTERM, quit);
    signal(SIGUSR1, toggle_debug);
    signal(SIGUSR2, toggle_modbus_debug);

    // create HAL component 
    p->hal_comp_id = hal_init(p->modname);
    if ((p->hal_comp_id < 0) || (connection_state == DONE)) {
        fprintf(stderr, "%s: ERROR: hal_init(%s) failed: HAL error code=%d\n",
                p->progname, p->modname, p->hal_comp_id);
        retval = p->hal_comp_id;
        goto finish;
    }

    // grab some shmem to store the HAL data in
    p->haldata = (haldata_t *)hal_malloc(sizeof(haldata_t));
    if ((p->haldata == 0) || (connection_state == DONE)) {
        fprintf(stderr, "%s: ERROR: unable to allocate shared memory\n", p->modname);
        retval = -1;
        goto finish;
    }
    if (hal_setup(p->hal_comp_id,p->haldata, p->modname))
        goto finish;

    set_defaults(p);
    hal_ready(p->hal_comp_id);

    DBG("using libmodbus version %s\n", LIBMODBUS_VERSION_STRING);

    connection_state = OPENING;
    if ((p->ctx = modbus_new_rtu(p->device, p->baud, p->parity, p->bits, p->stopbits)) == NULL) {
        fprintf(stderr, "%s: ERROR: modbus_new_rtu(%s): %s\n",
                p->progname, p->device, modbus_strerror(errno));
        goto finish;
    }
    DBG("device(%s) baud(%d) parity(%s) bits(%d) stopbits(%d)\n", p->device, p->baud, &(p->parity), p->bits, p->stopbits);
    if (modbus_set_slave(p->ctx, p->slave) < 0) {
        fprintf(stderr, "%s: ERROR: invalid slave number: %d\n", p->modname, p->slave);
        goto finish;
    }
    if ((retval = modbus_connect(p->ctx)) != 0) {
        fprintf(stderr, "%s: ERROR: couldn't open serial device: %s\n", p->modname, modbus_strerror(errno));
        goto finish;
    }
    DBG("%s: serial port %s connected\n", p->progname, p->device);

    modbus_set_debug(p->ctx, p->modbus_debug);
    if (modbus_set_slave(p->ctx, p->slave) < 0) {
        fprintf(stderr, "%s: ERROR: invalid slave number: %d\n", p->modname, p->slave);
        goto finish;
    }

    connection_state = CONNECTED;
    while (connection_state != DONE) {

        while (connection_state == CONNECTED) {
            if ((retval = read_data(p->ctx, p->haldata, p))) {
                p->modbus_ok = 0;
            } else {
                p->modbus_ok++;
            }
            if (p->modbus_ok > MODBUS_MIN_OK) {
                *(p->haldata->modbus_ok) = 1;
            } else {
                *(p->haldata->modbus_ok) = 0;
            }
            if ((retval = write_data(p->ctx, p->haldata, p))) {
                p->modbus_ok = 0;
                if ((retval == EBADF || retval == ECONNRESET || retval == EPIPE)) {
                    connection_state = RECOVER;
                }
            } else {
                p->modbus_ok++;
            }
            if (p->modbus_ok > MODBUS_MIN_OK) {
                *(p->haldata->modbus_ok) = 1;
            } else {
                *(p->haldata->modbus_ok) = 0;
            }
            /* don't want to scan too fast, and shouldn't delay more than a few seconds */
            if (p->haldata->looptime < 0.001) p->haldata->looptime = 0.001;
            if (p->haldata->looptime > 2.0) p->haldata->looptime = 2.0;
            loop_timespec.tv_sec = (time_t)(p->haldata->looptime);
            loop_timespec.tv_nsec = (long)((p->haldata->looptime - loop_timespec.tv_sec) * 1000000000l);
            if (!p->haldata->max_speed)
                nanosleep(&loop_timespec, &remaining);
        }

        switch (connection_state) {
        case DONE:
            // cleanup actions before exiting.
            modbus_flush(p->ctx);
            // clear the command register (control and frequency override) so panel operation gets reactivated
            if ((retval = modbus_write_register(p->ctx, REG_COMMAND1, 0)) != 1) {
                // not much we can do about it here if it goes wrong, so complain
                fprintf(stderr, "%s: failed to release VFD from bus control (write to register 0x%x): %s\n",
                        p->progname, REG_COMMAND1, modbus_strerror(errno));
            } else {
                DBG("%s: VFD released from bus control.\n", p->progname);
            }
            break;

        case RECOVER:
            DBG("recover\n");
            set_defaults(p);
            p->read_initial_done = 0;
            // reestablish connection to slave

            modbus_flush(p->ctx);
            modbus_close(p->ctx);
            while ((connection_state != CONNECTED) &&
                    (connection_state != DONE)) {
                sleep(p->reconnect_delay);
                if (!modbus_connect(p->ctx)) {
                    connection_state = CONNECTED;
                    DBG("rtu/tcpclient reconnect\n");
                } else {
                    fprintf(stderr, "%s: recovery: modbus_connect(): %s\n",
                            p->progname, modbus_strerror(errno));
                }
            }

            break;
            default: ;
        }
    }
    retval = 0;	

    finish:
    windup(p);
    return retval;
}