Re: pyepics not updating pv.enum_strs after connection

[Matt Newville <newville@cars.uchicago.edu>]

Hi Jamie,

On Wed, Mar 18, 2015 at 6:26 PM, Jameson Graef Rollins <jrollins@ligo.caltech.edu> wrote:

On Wed, Mar 18 2015, Jameson Graef Rollins <jrollins@ligo.caltech.edu> wrote:
> Hi, folks.  I'm having an issue with pyepics and ENUM records.  I'm
> initializing a PV from a device as follows:
>
> dev = Device(prefix)
> pv = dev.PV(attr, connect=False, connection_callback=connection_callback)
> pv.add_callback(callback)
>
> This all seems to work fine and as expected, except that the pv supplied
> as a keyword argument to the connection_callback and callback functions
> never has the pv.enum_strs attribute set for ENUM records, even after
> connection has been established.  This means the ENUMs can't ever be
> resolved as strings.

Sorry, just to clarify, if I do *not* set connect=False when
initializing dev.PV, then the enum_strs attribute is set properly.  In
other words, it appears to only be set if the pv is able to connect on
initialization.  If connect=False, the created pv does not get enum_strs
set, nor does it ever even after a connection has been made.

jamie.

Sorry for the confusion.  The surest way to ensure you have enum strings and other CTRL attributes is to do

   pv.get_ctrlvars()

This should happens by default in many situations where you need to know the CTRL variables (say, putting a string for the name to enum PV, or getting with 'as_string=True').  Of course, a PV can't get look up its enum strings if it's not connected.

Hope that helps,

--Matt Newville