Re: detecting remote PV disconnect (asyn)

[Michael Davidsaver via Tech-talk <tech-talk at aps.anl.gov>]

On 3/24/20 2:03 AM, Hinko Kocevar wrote:
> Michael, 
> 
>>> Yes LAB-
>>> EVR-000:EvtECnt-I.TIME is on EVR IOC. Using MS flag there makes me think that alarm severity would be propagated to the record holding TSEL (I have never done this before so I might be wrong on this assumption).
> 
>> Normally yes, but .TIME is handled as a special case, so I wouldn't be surprised
>> if this didn't work.  I'd recommend using an additional longin record to subscript
>> to the value of the event Cnt-I PV.  Then forward link from this to your records.
> 
> I'm after the timestamp of the Cnt-I record. I'm not sure I understand how to go about and implement your proposal.

Actually, thinking about it further, you can do:

record(stringin, "$(P)$(R)TimestampIn") {
    field(DTYP, "Soft Timestamp")

    field(SDIS, "LAB-EVR-000:EvtECnt-I CP MS") # not .TIME
    field(DISV, "-1")

    field(TSEL, "LAB-EVR-000:EvtECnt-I.TIME CA") # not CP
    field(INP,  "@%s.%f")
    field(FLNK, "$(P)$(R)Timestamp.PROC PP MS")
    info(autosaveFields, "TSEL")
}

This will work so long as the remote PV never has the value -1,
which an event counter should not.

Alarms should be propagated because the SDIS link is read with dbGetLink().
Then, so long as the value read is !=DISV the record is scanned.
The TSEL link, as a regular CA_LINK, is fetching time from the last received update.