Experimental Physics and
Industrial Control System

I'm sorry but it's not very clear to me what you mean with "Monitor the .VAL for alarm state changes  STAT and SEVR values are part of that metadata (...)".

Please, I would really appreciate it if you could show me using my provided sample code.

Thank you very much!

In Channel Access, request get the DBR_CTRL_DBL. The menu is part of the metadata. Monitor the .VAL for alarm state changes  STAT and SEVR values are part of that metadata. In pvAccess, alarm strings are supported. Records and drivers are not yet taking advantage of that.

On Thu, Jan 17, 2019, 5:14 AM rperez via Tech-talk <[email protected] wrote:

Hello,

I am developing a CA client program in C and I need to handle the severity value for the alarm limits (HIHI, HIGH, LOW, LOLO). This is, the value of HHSV, HSV, LSV and LLSV fields.

To do this, I am executing the following code:

    struct dbr_ctrl_double    tPvData;
    double data;
    chid    mychid;

    SEVCHK(ca_context_create(ca_disable_preemptive_callback),"ca_context_create");
    SEVCHK(ca_create_channel("PC:MEM_USED",NULL,NULL,10,&mychid),"ca_create_channel failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");

    SEVCHK(ca_get(DBR_DOUBLE,mychid,(void *)&tPvData),"ca_get failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");

     printf("PV Name %s :\n \talarm status: %d\n \talarm severity: %d\n \tvalue: %f\n \tunits: %s\n \talarm limits: [%d-%d]\n \twarning limits: [%d-%d]\n",
                               "PC:MEM_USED",  tPvData.status, tPvData.severity, tPvData.value, data.units,
                                tPvData.lower_alarm_limit, tPvData.upper_alarm_limit,
                                tPvData.lower_warning_limit, tPvData.upper_warning_limit);

    SEVCHK(ca_get(DBR_DOUBLE,mychid,(void *)&data),"ca_get failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    printf("PV Name %s=%f\n","PC:MEM_USED", data);

    return(0);

As result I get the following PV's data, even the alarm (HIHI, LOLO) and warning (HI, LO) limits.

PV Name PC:MEM_USED  :
     alarm status: 3
     alarm severity: 2
     value: 100.000000
     units: %
     alarm limits: [nan-95.000000]
     warning limits: [nan-85.000000]

     PV Name PC:MEM_USED =100.000000

But to get the HHSV, HSV, LSV and LLSV fields, I am doing the following:

    SEVCHK(ca_create_channel("PC:MEM_USED.HHSV",NULL,NULL,10,&mychid),"ca_create_channel failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    SEVCHK(ca_get(DBR_DOUBLE,mychid,(void *)&data),"ca_get failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    printf("%s= %f\n","PC:MEM_USED.HHSV",data);

    SEVCHK(ca_create_channel("PC:MEM_USED.HSV",NULL,NULL,10,&mychid),"ca_create_channel failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    SEVCHK(ca_get(DBR_DOUBLE,mychid,(void *)&data),"ca_get failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    printf("%s= %f\n","PC:MEM_USED.HSV",data);

    SEVCHK(ca_create_channel("PC:MEM_USED.LLSV",NULL,NULL,10,&mychid),"ca_create_channel failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    SEVCHK(ca_get(DBR_DOUBLE,mychid,(void *)&data),"ca_get failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    printf("%s= %f\n","PC:MEM_USED.LLSV",data);

    SEVCHK(ca_create_channel("PC:MEM_USED.LSV",NULL,NULL,10,&mychid),"ca_create_channel failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    SEVCHK(ca_get(DBR_DOUBLE,mychid,(void *)&data),"ca_get failure");
    SEVCHK(ca_pend_io(5.0),"ca_pend_io failure");
    printf("%s=%f\n","PC:MEM_USED.LSV",data);

As result, I am getting this:

     "PC:MEM_USED.HHSV=2.000000" which means severity for a Hihi alarm is MAJOR

     "PC:MEM_USED.HSV=1.000000" which means severity for a Hi alarm is MINOR

     "PC:MEM_USED.LLSV=0.000000" which means severity for a Lolo alarm is NO_ALARM

     "PC:MEM_USED.LSV=0.000000" which means severity for a Lo alarm is NO_ALARM

Taking this into account, I have the following doubts:

1. Is the value of the alarm severity  filed = 2 (MAJOR ) derived from this HHSV alarm severity limit field?  or is it only a coincidence that the value of the alarm severity is also 2 (MAJOR)? If so, what is the difference between the alarm severity field and the severity for a Hihi alarm field (HHSV)?

2. Is this the correct way ( this is executing ca_get (PC:MEM_USED.HHSV), etc...) to obtain these HHSV, HSV, LLSV and LSV values?  Is there any other simpler way?

Thank you very much in advance.