Re: Device with INP as a PV_LINK

[Andrew Johnson <anj@aps.anl.gov>]

Let me fix the errors in my example, this is now tested (I added it to 
the example's dbSubExample.db file):

# put 'Tick' to clock to start everything off
record(bo, "$(user):clock") {
  field(ZNAM, "Tock")
  field(ONAM, "Tick")
  field(HIGH, "5")
  field(FLNK, "$(user):timeNow")
}
# timeNow reports the timestamp from clock
record(stringin, "$(user):timeNow") {
  field(TSEL, "$(user):clock.TIME")
  field(DTYP, "Soft Timestamp")
  field(INP, "@%Y-%m-%d %H:%M:%S.%09f")
  field(FLNK, "$(user):drWho")
}
# drWho is 10 seconds behind the rest of us
record(sub, "$(user):drWho") {
  field(TSE, "-2")
  field(SNAM, "timeTravel")
  field(INPA, "-10")
  field(FLNK, "$(user):tardis")
}
# tardis reports where the doctor is
record(stringin, "$(user):tardis") {
  field(TSEL, "$(user):drWho.TIME")
  field(DTYP, "Soft Timestamp")
  field(INP, "@%Y-%m-%d %H:%M:%S.%09f")
}


I put this into the dbSubExample.c file:

static long timeTravel(subRecord *precord)
{
    epicsTimeGetCurrent(&precord->time);
    epicsTimeAddSeconds(&precord->time, precord->a);
    return 0;
}
epicsRegisterFunction(timeTravel);


And this in the dbSubExample.dbd file:

function(timeTravel)


This is the result:

  cau:  put anjHost:clock Tick
     anjHost:timeNow 14:39:35.021182600 2006-09-06 14:39:35.021182600
      anjHost:tardis 14:39:25.021356680 2006-09-06 14:39:25.021356680
     anjHost:timeNow 14:39:40.025729720 2006-09-06 14:39:40.025729720
      anjHost:tardis 14:39:30.025885560 2006-09-06 14:39:30.025885560


Hmm, I wonder what some of the EPICS client tools would do if they see 
the doctor travelling backwards in time (i.e. get an earler timestamp 
from him *after* receiving a later one)...

- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger