Experimental Physics and
Industrial Control System

>  I am using an old mvme-177 IOC to serve these PV, so that may make matters worse

 

If it’s an older EPICS release, the DBE_PROPERTY might not be supported.

You can look in the EPICS base release notes to see when DBE_PROPERTY was introduced, but note that this happened in stages.

Initially, I think it only covered changes in enum PV labels, then support for changing units, precision, limits, … was added in various steps.

 

To test from the command line, you’d want to monitor for DBR_CTRL_DOUBLE with DBE_PROPERTY in one terminal, and for DBR_TIME_DOUBLE with DBE_VALUE in another window. The first one should show updates for only property changes, the latter for any value change.

Unfortunately, only ‘caget’ allows setting the DBR_... request type, while only ‘camonitor’ allows setting the DBE_... event type, so you can’t fully replicate this from the command line.

The closest would be:

 

# Fetch the control info once (can’t monitor)

caget -d DBR_CTRL_DOUBLE ThePV

 

# Monitor for ‘property’ changes (DBE_PROPERTY, but can’t request DBR_CTRL_DOUBLE  for the type)

camonitor -m p ThePV