Ethercat installation summary

  if (home) {
    opmode = OPMODE_HOMING;
    if (opmode_homing) {
      controlword |= (home << 4);
    }
}

  //home states
  if (opmode_homing) {
    // hack
    pos_fb = pos_cmd;
    stat_homed = ((statusword >> 10) & 1) && ((statusword >> 12) & 1);
    stat_homing = !stat_homed && !((statusword >> 10) & 1);
  }

FUNCTION(read_all) {
  // read Modes of Operation
  opmode_no_mode = (opmode_display == OPMODE_NONE);
  opmode_homing = (opmode_display == OPMODE_HOMING);
  opmode_cyclic_velocity = (opmode_display == OPMODE_CYCLIC_VELOCITY);
  opmode_cyclic_position = (opmode_display == OPMODE_CYCLIC_POSITION);
 
  // read status
  stat_switchon_ready    = (statusword >> 0) & 1;
  stat_switched_on       = (statusword >> 1) & 1;
  stat_op_enabled        = (statusword >> 2) & 1;
  stat_fault             = (statusword >> 3) & 1;
  stat_voltage_enabled   = (statusword >> 4) & 1;
  stat_quick_stop        = (statusword >> 5) & 1;
  stat_switchon_disabled = (statusword >> 6) & 1;
  stat_warning           = (statusword >> 7) & 1;
  stat_remote            = (statusword >> 9) & 1;

  if (opmode_cyclic_position || opmode_cyclic_velocity) {
    stat_target_reached = (statusword >> 10) & 1;
  } else {
    stat_target_reached = 0;
  }

  //home states  
  if (opmode_homing) {
    stat_homed    = ((statusword >> 10) & 1) && ((statusword >> 12) & 1);
    stat_homing   = !stat_homed && !((statusword >> 10) & 1);
  } else if (opmode_homing_old) {
    home_offset = drv_actual_position;
  }

  opmode_homing_old = opmode_homing;

  // check for change in scale value
  check_scales(&pos_scale, &pos_scale_old, &pos_scale_rcpt);
  check_scales(&velo_scale, &velo_scale_old, &velo_scale_rcpt);

  // read position feedback
  pos_fb = ((double)(drv_actual_position - home_offset)) * pos_scale_rcpt;

  if (opmode_homing) {
    // hack
    pos_fb = pos_cmd;
  }

  // read velocity feedback
  velocity_fb = ((double)drv_actual_velocity) * velo_scale_rcpt;


  // update fault output
  if (auto_fault_reset_delay > 0) {
    auto_fault_reset_delay -= period;
    drv_fault = 0;
  } else {
    drv_fault = stat_fault && enable;
  }
}

//local data
//CIA Control Word
typedef union
{
  struct
  {
    unsigned char SwitchOn        : 1;  // 00
    unsigned char EnableVoltage   : 1;  // 01
    unsigned char QuickStop       : 1;  // 02
    unsigned char EnableOperation : 1;  // 03
    unsigned char StartHome       : 1;  // 04 not used in CSP or homing
    unsigned char bit5            : 1;  // 05 not used in CSP or homing
    unsigned char bit6            : 1;  // 06 not used in CSP or homing
    unsigned char Faultreset      : 1;  // 07
    unsigned char Timeout         : 1;  // 08
    unsigned char bit9            : 1;  // 09 not used in any mode
    unsigned char keep            : 6;  // 10-15 not used in any mode
  }b;
    hal_u32_t Word;
}Control_t;

//CIA Status Word
typedef union
{
  struct
  {
    unsigned char ReadyToSwitchOn  : 1;  // 00
    unsigned char SwitchOn         : 1;  // 01
    unsigned char OperationEnabled : 1;  // 02
    unsigned char Fault            : 1;  // 03
    unsigned char VoltageEnabled   : 1;  // 04
    unsigned char QuickStop        : 1;  // 05
    unsigned char SwitchOnDisabled : 1;  // 06
    unsigned char Warning          : 1;  // 07
    unsigned char keep1            : 1;  // 08
    unsigned char Remote           : 1;  // 09
    hal_bit_t     TargetReached    : 1;  // 10
    unsigned char bit11            : 1;  // 11
    unsigned char bit12            : 1;  // 12
    unsigned char keep2            : 3;  // 13-15
  }b;
    hal_u32_t Word;
}Status_t;

    Status_t     Status;          // IN  - CIA Status Word with bitmap
    Control_t    Control;         // OUT - CIA Control Word with bitmap 

Status.Word // the full word
Status.StartHome // the bit set to start homing

[code]pos_fb = pos_cmd;" and still noticed jumping. After looking at some Halscope traces it became apparent that the drive was being put back into cyclic position mode before the position register was cleared from homing. I made a small change in order of a few lines of code forcing the homing procedure in the drive to finish before setting the drive back to position mode. 

  // OP Mode
  // set to position mode
  if (stat_voltage_enabled && !home ) {
    opmode = OPMODE_CYCLIC_POSITION;
  }
  // set velo mode
  if (stat_voltage_enabled && !pos_mode && !home) {
    opmode = OPMODE_CYCLIC_VELOCITY;
  }
 
  // reset home command  
  if (home && (stat_homed && !stat_homed_old) && opmode_homing) {
    home = 0;  
  }