"Channel for PV <PV Name> already exists"

rlodico06 commented 1 month ago

A common message in the log is "Channel for PV {PV Name} already exists". This message is not reported by femto.py; however, it is usually accompanied by the message "PV READ ERROR", which is reported by femto.py and is thrown when an exception occurs while to to connect/get a PV value.

This issue is particularly problematic for the phase motor's wait_for_stop function because the loop repeatedly tries to connect to this PV, meaning the connection error message gets written over and over again.

rlodico06 commented 1 month ago

@christina-pino @ljansen7 Do either of you know where this message is reported from? If we wanted to, do you know how we might prevent this message from being written to the log?

rlodico06 commented 3 weeks ago

Found where this message is being written from: /reg/g/pcds/pkg_mgr/release/las-0.0.2/x86_64-rhel7-gcc48-opt/python/psp/Pv.py

There does not seems to be a method for suppressing print statements.
We could comment/remove the particular print statements that spam the log, but we need to find out which other scripts point to this Pv.py file.
If it is only the femto scripts, then it is probably safe to comment them out.

slaclab / femto-timing

"Channel for PV <PV Name> already exists" #28