Experimental Physics and
Industrial Control System

Jure Varlec via Tech-talk <tech-talk at aps.anl.gov> · Tue, 26 May 2020 11:19:21 +0200

Hello Simon,

What happens if you use wait_for_connection() instead of connect()? When you
construct a PV object, it will start connecting on its own, so you just need to
wait. AFAICT, the codepaths for wait_for_connection() and connect() are
different, so you may get better results.

Best
Jure

On Tuesday, 26 May 2020 10:47:48 CEST Simon Rose via Tech-talk wrote:
> Hello all –
> 
> I am trying to set up something to do some automated testing of communication with a running IOC with PyEpics, but unfortunately I am running into some inconsistent behavior which makes it difficult to use as a reliable testing mechanism.
> 
> Specifically, if I have an IOC (EPICS base 7.0.3.1) up and running on the same machine, and run the following script:
> 
> from epics import PV
> pv = PV(“test”)
> assert pv.connect()
> 
> then most of the time, this works exactly as intended. However, somewhere around 1 in 5 times or so, it fails. I have tried to look at the network traffic (using Wireshark) between the IOC and the python client, but unfortunately I don’t see a difference between successful and unsuccessful connection attempts.
> 
> I am running both IOC and client inside a linux VM on my mac.
> 
> Any help would be appreciated,
> 
> Cheers,
> 
> Simon
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System