Understand put requests

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

Dear Colleague,

I'm building something to deal with the real device controls and came
across some issues. Some power supply devices could not be changed
during the running of optimization routines, which is executing the CA
put requests repeatedly, not very fast, a few seconds per iteration. 

Since I'm not the device IOC creator, my understanding is that possibly
the specific device does not respond to the request promptly, the
questions are:

- How does a device control IOC to respond a new incoming change
request if it's still processing one?
- Is there any way to know that the PV is ready to take a new change
request?
- Or is there any way to signal the PV to ignore any processed request
but take the latest request?

To my point of view as an application developer, the expected behavior
is the device only process the latest request and drop the one that is
under processing. But before talking with the responsible engineer, I
would like to fully understand this problem.

Appreciate your help.

-- 
Tong Zhang <zhangt at frib.msu.edu>
Facility for Rare Isotope Beams, Michigan State University