Re: Problem reading SNMP Gauge32 values with devSnmp AI/LI records

["Priller, John via Tech-talk" <tech-talk at aps.anl.gov>]

Sorry, that should have been "Gauge32:" as the mask not "Gauge:" 

(when is AI going to be good enough to catch stupid mistakes I make?)

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From: Priller, John
Sent: Friday, March 13, 2026 5:46 PM
To: Varuna Crishan Meddage; tech-talk at aps.anl.gov
Subject: Re: Problem reading SNMP Gauge32 values with devSnmp AI/LI records

 

Varuna;

Is this an integer value you're trying to read?  In that case I'd suggest a longin record type using this for your INP field:

field(INP, "@$(HOST) $(COMMUNITY) $(W)::nsFaultSatView1.$(id) Gauge: 100 i")

Here "Gauge:" is the mask for what to strip away and the integer value is what's left after it.

The 'i' is optional for an input field, but would be needed if you wanted to read the value in a native integer format by adding the 'n' flag.  That's what this INP below does, instead of the above example which reads the value as a string and then converts to an integer.

field(INP, "@$(HOST) $(COMMUNITY) $(W)::nsFaultSatView1.$(id) Gauge: 100 in")

This saves a miniscule amount of processing time by skipping the string-to-int conversion.  The native flag is usually used with floats, to achieve better precision.

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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: Friday, March 13, 2026 5:13 PM
To: tech-talk at aps.anl.gov
Subject: Problem reading SNMP Gauge32 values with devSnmp AI/LI records

 

[EXTERNAL] This email originated from outside of FRIB

Hi all,

I am trying to read SNMP Gauge32 variables from a Novus GPS device using the devSnmp EPICS driver. 

Here’s my setup:

-  community: novus

- SNMP variable: NOVUS-SECURE-MIB::nsFaultSatView1.0 (Gauge32)

- Record type: stringin / ai / longin (tried multiple)

- Template snippet:

record(stringin, "$(acc):$(sys)_$(group):nsFaultSatView1")

{

  field(DTYP, "Snmp")

  field(INP, "@$(HOST) $(COMMUNITY) $(W)::nsFaultSatView1.$(id) 1 100 s")

  field(SCAN, "10 second")

}

When I start the IOC, I get:

2026/03/13 15:31:50 devSnmp SI read error '<PREFIX>:nsFaultSatView1' : mask '0' not found in 'Gauge32: 14'

I have tried:

- Using `mask = 0`, `1`, `-1`, `0xffffffff`, `*`

- Switching to `ai` or `longin` record types

- Using `:raw` in the OID

- Reading via `stringin` + calc record

All attempts fail with the "mask not found" error.

Question

Is there a way to read **Gauge32 numeric SNMP variables** using  devSnmp?  

Any guidance would be appreciated!

Thanks,

Varuna