Experimental Physics and
Industrial Control System

[email protected] (Bob Dalesio) · Mon, 2 Oct 95 15:22:41 MDT

  I was working on the steppermotor record a little at CEBAF and
  found a number of problems - most of them related to using the
  IALG field to move to one of the limits on initialization. There
  are also problems with PASSIVE motors with no retry count and
  monitors of the mcw and mccw fields. The fixes are below. Please
  review and put into 3.12.2.

  Also - it should be understood that the OMS motors determine that
  they have finished moving when the position is the same on 3
  subsequent reads (100 milliseconds) - so if the motor is moving
  very slowly - VELO is too small - the readback RBV for the motor will
  not track the desired value VAL.

  ****************************************************************
  if you initialize to a limit - the overshoot will stop the motor
  ****************************************************************
  --- in the source it reads --
  /* stop motor on overshoot */
  if (psm->movn){

  --- should be ----

  /* stop motor on overshoot */
  if (psm->movn && (psm->init == 1)){
  ****************************************************************

  ****************************************************************
  if you initialize to a limit and the retry count is not 0 ---
  ****************************************************************
  --just after the overshoot check at the same level of indentation

  if(!psm->movn) {

  --should be:

  if(!psm->movn && (psm->init == 1)) {

  ****************************************************************

  ****************************************************************
  if you are using init to a limit in IALG - the move is too big
  ****************************************************************
  status = (*pdest->sm_command)(psm,SM_MOVE,0xfffffff,0);
  ---and
  status = (*pdest->sm_command)(psm,SM_MOVE,-0xfffffff,0);

  ---should be

  status = (*pdest->sm_command)(psm,SM_MOVE,0xffffff,0);
  ---and
  status = (*pdest->sm_command)(psm,SM_MOVE,-0xffffff,0);
  -----(one less f)
  ***************************************************************

  ***************************************************************
  if you are using the fields MCW and MCCW to monitor limits -
  they are not being posted.....
  ***************************************************************
  ---after 

  db_post_events(psm,&psm->cw,DBE_VALUE|DBE_LOG);
  ---and
  db_post_events(psm,&psm->ccw,DBE_VALUE|DBE_LOG);

  ---add

  db_post_events(psm,&psm->mcw,DBE_VALUE|DBE_LOG);
  ---and
  db_post_events(psm,&psm->mccw,DBE_VALUE|DBE_LOG);

  --- you also need to put these statements in { ... }
  *****************************************************************

  *****************************************************************
  a passive motor record being set by a slider may not get processed
  again when the final value is put in the record - occurs if the
  record is being processed while new values are being put in the
  record as well.
  *********************************************************************
  --- in the retry portion of the code

  if (psm->rcnt < psm->rtry){

  --- should be

  if ((psm->rcnt < psm->rtry) || (psm->lval != psm->val)){
  	psm->lval = psm->val;
  **********************************************************************

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System