Re: 答复: Get a time difference in EPICS database

[Tim Mooney <mooney@aps.anl.gov>]

Hi hongchunxia,
 

----- Original Message -----
> From: "洪春霞" <hongchunxia@sinap.ac.cn>
> To: "Tim Mooney" <mooney@aps.anl.gov>
> Cc: tech-talk@aps.anl.gov
> Sent: Saturday, November 24, 2012 5:52:34 AM
> Subject: 答复: Get a time difference in EPICS database
> Hi,
> 
> Thank you for your reply.
> 
> What I want to do is as follows:
> 1) First I want to have a judgement on the value of A and B in
> record(calcout,"h:time_difference"), if A=B, I will get the time2
> (h:Systemtime2).
> so I want to cause h:Systemtime2 to process just in the time of
> A=B,and if A is not equal to B, the h:Systemtime2 should not be
> processed.
> so in record(stringin,"h:Systemtime2"), I use field(DISV,"0") and
> field(SDIS,"***"),because If DISV=DISA, the record will be disabled,
> so I
> think if I set DISV!=DISA, the record will be enabled, but I do not
> know whether is it right?

By setting SDIS, you've made sure that h:Systemtime2 will not be processed
if A!=B, but there is nothing that makes h:Systemtime2 process if A==B.

How about this:

record(calcout,"h:check_status")
{
    field(DESC,"if status==3, get time2 and calc time diff")
    field(CALC,"A=B")
    field(INPA,"h:status PP NMS")
    field(INPB,"3")
    field(OUT,"h:calc_time_diff.PROC PP NMS")
    field(OOPT,"Transition To Non-zero")
}
record(calcout,"h:calc_time_diff")
{
    field(DESC,"get time2 and calc time diff")
    field(CALC,"C-D")
    field(INPC,"h:Systemtime1 NPP NMS")
    field(INPD,"h:Systemtime2 PP NMS")
}

If h:Systemtime1 gets processed once when the ioc boots and never again, then
h:calc_time_diff.VAL will be the number of seconds after boot that h:status was
found equal to 3.  It won't be the time that the h:status /changed/ to 3, but
instead the time h:status was checked and found equal to 3.  If you want to
check h:status whenever it changes, you could replace
    field(INPA,"h:status PP NMS")
with
    field(INPA,"h:status CP NMS")

This will cause h:check_status to process whenever a new value of h:status is posted.

> 2) I want to cause a recond to process just when some requirements
> were met in the EPICS database, for example, in field
> (CALC,"A=B?(C-D):0"),
> I want to cause some reconds to process according to the different
> results of CALC, that is, a record is processed when A=B, and another
> record is processed when A!=B,
> Now I do not know how to do?

You can do this with a fanout or seq record.

record(calcout,"choose") {
    field(INPA,"status")
    field(INPB,"3")
    field(CALC,"a=b?1:2")
    field(OUT,"switch.SELN PP")
}
record(fanout,"switch") {
    field(SELM,"Specified")
    field(LNK1,"process_me_when_a_is_b")
    field(LNK2,"process_me_when_a_is_not_b")
}

> Thank you so much. Best Wishes.
> 
> ------------------------------------------
> hongchunxia
> 
> 
> 
> -----Original Message-----
> From: Tim Mooney [ mailto:mooney@aps.anl.gov ]
> Sent: 2012-11-24 (星期六) 12:46
> To: 洪春霞
> Cc: tech-talk@aps.anl.gov
> Subject: Re: Get a time difference in EPICS database
> 
> hongchunxia,
> Two things:
> 
> 1) If you are using the soft time device support in EPICS base, and
> you want to use a calc record to calculate the time difference, you
> should not get the time as a formatted string, but instead get it as
> the raw number of seconds since the fixed "epoch" (which I think is
> some time back in 1990 or something):
> 
> record(ai,"time1") {
> field(DTYP, "Soft Timestamp")
> }
> record(ai,"time2") {
> field(DTYP, "Soft Timestamp")
> }
> record(calcout,"timeDiff") {
> field(DESC,"time2-time1 (seconds)")
> field(INPA,"time1 NPP")
> field(INPB,"time2" NPP)
> field(CALC,"b-a")
> }
> 
> 2) I don't see anything in your database that would cause
> h:Systemtime2 to process. I think your job might be easier if you
> separate the job of deciding whether h:Systemtime2 should process,
> from the job of calculating the difference between h:Systemtime1 and
> h:Systemtime2.
> 
> Tim Mooney
> 
> ----- Original Message -----
> From: "洪春霞" <hongchunxia@sinap.ac.cn>
> To: tech-talk@aps.anl.gov
> Sent: Friday, November 23, 2012 2:07:26 AM
> Subject: Get a time difference in EPICS database
> 
> 
> 
> 
> Hi,
> I want to get a time difference in EPICS database, the record of
> h:Systemtime1 is run when ioc is start, that is, it is the realtime
> time.
> The record of h:Systemtime2 is get when A=3 in the
> record(calcout,"h:monitor_time"), and it should be executed once, but
> now I can not get the time of h:Systemtime2.
> When I input “camonitor h:Systemtime2” in another Terminal, I always
> get “h:Systemtime2 <underfined> UDF INVALID”,and I input “camonitor
> h:time_plus” in another Terminal, I get the time is the value of C.
> That is to say, the record of h:Systemtime2 is not executed.
> 
> Can you give me some advice? Thank you very much.
> Best Wishes.
> 
> The database which I use is as follows:
> 
> record(ai, "h:status")
> {
> }
> record(stringin,"h:Systemtime1")
> {
> field(DESC,"Systemtime1")
> field(DTYP,"Soft Timestamp")
> field(SCAN,"1 second")
> field(PINI,"YES")
> field(INP,"@%s")
> }
> record(stringin,"h:Systemtime2")
> {
> field(DESC,"Systemtime2")
> field(DTYP,"Soft Timestamp")
> field(INP,"@%s")
> field(DISV,"0")#If DISV=DISA, then the record will be disabled
> field(SDIS,"h:monitor_time PP MS")#
> }
> #This is the value that is compared with DISV to determine if the
> record is
> #disabled. Its value is obtained via SDIS if SDIS is a database or
> channel access
> #link.
> record(calcout,"h:time_difference")
> {
> field(CALC,"A=B?(C-D):0")
> field(INPA,"h:status PP NMS")
> field(INPB,"3")
> field(INPC,"h:Systemtime1 PP NMS")
> field(INPD,"h:Systemtime2 NPP NMS")
> field(OUT,"h:time_plus PP NMS")
> field(OOPT,"Transition To Non-zero")
> }
> ------------------------------------------
> hongchunxia
> 
> --
> Tim Mooney (mooney@aps.anl.gov) (630)252-5417
> Software Services Group (www.aps.anl.gov)
> Advanced Photon Source, Argonne National Lab

-- 
Tim Mooney (mooney@aps.anl.gov) (630)252-5417
Software Services Group (www.aps.anl.gov)
Advanced Photon Source, Argonne National Lab