Experimental Physics and
Industrial Control System

[email protected] (Bob Dalesio) · Fri, 17 Jun 94 11:28:47 MDT

  I am not sure what version of the OMS driver is in use by the CAT's, but the 
  original driver uses the interupts to get data back from the OMS.
  Polls the motor at 30Hz when it is moving and notifies the database at 10Hz
  or immediately when the motor stops. This is a maximum latency of 
  ~34 milliseconds. I've attached the code segments. My memory is not great,
  but I seem to remember something about the end of move interrupt not
  working. That would be the lowest latency response. If someone checks that
  out and determines that it works, let me know so that we can incorporate it
  immediately, thanks.

  The CPU usage on this driver was realtively small as I recall. It is only active
  when there is a motor in use, and the overhead to send position requests is
  minimal - about 10usecs per byte.

  I would be very interested in beta testing their PAL. I was too quick to
  delete that message - could someone give me a contact at OMS? Is this only
  available on the OMS-8? To date, we've been able to use the same driver for all
  of their cards.

  	Bob

  ===============================================================
  OMS interrupt for data ready from the card:

  oms_intr(card)
  register short  card;
  {
      register struct vmex_motor  *pmotor;
      register int                key;
      register char               inp_char;
      register int                *pinx;

      key = intLock();

      /* pointer to this motor */
      if ((pmotor = oms_motor_present[card]) == 0){
          intUnlock(key);
          return(0);
      }
      pinx = &resp_inx[card];

      /* get the next character */
      if (pmotor->status & INPUT_BUFFER_FULL){

          /* check for end of command */
          inp_char = pmotor->data;
          if (((inp_char == 0xa) || (inp_char == 0xd)) && (*pinx > 0)){
              /* check if the encoder command caused an error */
              if (pmotor->status & (OMS_ENCODER | OMS_CMD_ERROR))
                  encoder_present[card] = FALSE;
              else encoder_present[card] = TRUE;
              /* terminate and send the message */
              read_buffer[card][*pinx] = 0;
              if (rngBufPut(oms_resp_q,read_buffer[card],OMS_MSG_SZ)
                != OMS_MSG_SZ){
                  logMsg("oms_resp_q full\n");
              }else{
                  semGive (oms_resp_sem);
              }
              *pinx = 0;        /* reset buffer */

          /* save printable ascii characters */
          }else if ((inp_char >= 0x20) && (inp_char < 0x7f)){
              if (*pinx == 0){
                  read_buffer[card][*pinx] = card;
                  *pinx += 1;
              }
              if (*pinx < OMS_MSG_SZ){
                  read_buffer[card][*pinx] = inp_char;
                  *pinx += 1;
              }else{
                 logMsg("oms intr buffer full\n");
              }
          }
      }
      intUnlock(key);
      return(0);
  }

  =================================================================
  Polls for motor position at 30 Hz when the motor is moving:
        while (motor_active){
              motor_active = FALSE;
              taskDelay(2);

  =====================================================================
  Notify at 10Hz or as soon as the motor stops:

                      /* post every .1 second or not moving */
                      if ((poms_motor_array->update_count-- <= 0) 
                        || (pmotor_data_array->moving == 0)){
                          if (poms_motor_array->callback != 0){
                              (int)psmcb_routine = poms_motor_array->callback;
                              (*psmcb_routine)(pmotor_data_array,poms_motor_array->callback_arg);
                          }
                          if (pmotor_data_array->moving){
                              poms_motor_array->update_count = 2;
                          }else{
                              poms_motor_array->update_count = 0;
                          }
                      }

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System