Re: Handling epicsParseDouble Errors from SNMP PVs Returning Empty or Unexpected Values

[Varuna Crishan Meddage via Tech-talk <tech-talk at aps.anl.gov>]

Hi John,

Thanks for the suggestion. I implemented that but still get the following error. May be need to contact the vendor to provide an updated MIB file to handle this kind of output.

====================================== ERROR =====================================

devSnmp AI read error 'PIP2:TIME_CTRL_GPS:nsRbDiscStatus' : epicsParseDouble failed on 'should be INTEGER): ""'

=========================================================================================

---

From: Priller, John <priller at frib.msu.edu>
Sent: Wednesday, March 18, 2026 11:36 AM
To: Varuna Crishan Meddage <vmeddage at fnal.gov>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: Handling epicsParseDouble Errors from SNMP PVs Returning Empty or Unexpected Values

 

[EXTERNAL] – This message is from an external sender

It looks to me like the device is returning "" and the net-snmp library complains this doesn't match what the MIB file declares it should be, an integer value.  Is there perhaps an updated MIB available from the manufacturer?

You could also specify the 'n' native flag in your INP field to avoid parsing strings altogether:

field(INP, "@$(HOST) $(COMMUNITY) $(W)::nsRbDiscStatus.$(id)  ( 100 in")

But I'm not sure what you'd get back.  There's some mismatch between the MIB and the device that needs to be addressed.

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Varuna Crishan Meddage via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, March 18, 2026 12:27 PM
To: tech-talk at aps.anl.gov
Subject: Handling epicsParseDouble Errors from SNMP PVs Returning Empty or Unexpected Values

 

[EXTERNAL] This email originated from outside of FRIB

I have the following EPICS record defined

==================================================================

record(ai, "$(acc):$(sys)_$(group):nsRbDiscStatus")

{

  field(SCAN, "10 second")

  field(DTYP, "Snmp")

  field(INP, "@$(HOST) $(COMMUNITY) $(W)::nsRbDiscStatus.$(id)  ( 100 i")

  field(DESC, "Rb Discipline Status")

  #field(HIGH,"2")

  #field(HIHI,"3")

  #field(LOW,"0")

  #field(LOLO,"-1")

  #field(LLSV, MAJOR)

  #field(LSV, MINOR)

  #field(HSV, MINOR)

  #field(HHSV, MAJOR)

}

===================================================================

For this EPICs record I get the following error during runtime.

devSnmp AI read error 'PIP2:TIME_CTRL_GPS:nsRbDiscStatus' : epicsParseDouble failed on 'should be INTEGER): ""'

In the MIB file this variable is defined as follows

======================================================================

nsRbDiscStatus OBJECT-TYPE

    SYNTAX      INTEGER { disciplinewait(0),disciplinegood(1),holdover(2) }

    MAX-ACCESS  read-only

    STATUS      current

    DESCRIPTION 

        "Rb Discipline Status: 0=Disc Wait, 1=Disc Good, 2=Holdover"

    ::= { nsRubidiumObjs 4 }

========================================================================

When I ran the snmpwalk command, the output for this variable is

NOVUS-SECURE-MIB::nsRbDiscStatus.0 = Wrong Type (should be INTEGER): ""

Any suggestions to solve this issue ?

Thanks

Varuna Meddage