asynPortDriver Question

["Szalata, Zenon M." <zms@slac.stanford.edu>]

Hi Mark,

I am using a four record set to write analog data to a set point register in a power supply and to keep reading and writing this register in sync.  This technique is what you suggested as a solution to a question I had.  Here are the four records:

 

#---- $(DESC) ------------------------------

record( ao, "$(P):AO:SC:$(ITEM)"){

  field( DESC, "$(DESC):")

  field( OUT,  "$(P):AO:$(ITEM) PP")

  field( DRVL, "$(DRVL)")

  field( DRVH, "$(DRVH)")

}

record( ao, "$(P):AO:$(ITEM)"){

  field( SDIS, "$(P):AO:$(ITEM):Sync.PACT")

  field( DISV, "1")

  field( DTYP, "asynFloat64")

  field( OUT,  "@asyn($(PORT),0,1)AO_$(ITEM)")

}

record( ai, "$(P):AI:$(ITEM)"){

  field( DTYP, "asynFloat64")

  field( INP,  "@asyn($(PORT),0,1)AI_$(ITEM)")

  field( SCAN, "I/O Intr")

  field( EGU,  "$(EGU)")

  field( FLNK, "$(P):AO:$(ITEM):Sync")

}

record( ao, "$(P):AO:$(ITEM):Sync"){

  field( DOL,  "$(P):AI:$(ITEM) NPP")

  field( OMSL, "closed_loop")

  field( OUT,  "$(P):AO:SC:$(ITEM) PP")

}

 

An EDM Text Control widget connected to the “AO:SC” record is used to write a new value to the set point register.  Depending on some other configuration parameters that the power supply is set up with, write set point might fail.  When that happens, my writeFloat64 routine returns asynError and the SEVR gets set INVALID in the “$(P):AO:$(ITEM)” record.  I would like the EDM widget to reflect this alarm condition.  It does not do it because it is not connected to the AO record that is in an alarm state and I don’t know how to transfer this alarm information to the record the EDM widget is connected to.

 

I wonder if it is possible to control alarm state of an EPICS record via asynPortDriver, a record that is not being processed at the moment?  That is, is there a way other than returning a failed completion code from a processing routine (like writeInt32) to put a record in an alarm state?

 

Thanks,

Zen