Re: asyn: what if a driver wants to force callbacks?

[Mark Davis <davism50@msu.edu>]

On 5/26/2016 1:52 AM, Torsten Bögershausen wrote:

I remember that Mark Rivers had said something about changing it so that a callback would happen for parameters for which the appropriate setXxxParam() function was called, even if the value had not changed.  And I THINK that it made it in to one of the more recent versions, but if so, I don't remember which one.

Mark Davis, FRIB/NSCL

To my knowledge,
there is no update.
In our driver, we do it like this:

    /* If not moving, trigger a record processing at low rate */
    if (!nowMoving) setDoubleParam(pC_->motorPosition_, newPositionInSteps + 1);
    setDoubleParam(pC_->motorPosition_, newPositionInSteps);

And I added a test case:
https://github.com/EuropeanSpallationSource/MCAG_Base_Project/blob/master/epics/test/500_DLY-STOP.py

Out of curiosity:
Which kind of device are you using ?


On 25/05/16 23:50, Ford, Christopher wrote:

Hi,

In 2015 there was some discussion on Tech-Talk about how to force a callback for a parameter that had not changed values.
Mark Rivers suggested a work-around, as shown below.
I wonder if anyone has an update on the situation since then?  Has any other method appeared?  Or did you have success with the work-around?

Thanks,
 -Chris Ford, SLAC

On16 Nov 2015 Mark Rivers writes:

If a driver wants to force a callback there is a method that does not require any changes to the base classes, e.g. exposing statusChanged_ as protected or adding a new
isMotorRecordnowFilterButAlwaysProcess_ flag.  The driver simply needs to set a parameter to a different value from present and then back to its current value, for example
 setDoubleParam(pC_->motorPosition_(position+1.);
 setDoubleParam(pC_->motorPosition_(position);
 callParamCallbacks();

-- 

Mark Davis
NSCL/FRIB Control Systems Software Engineer
davism50@msu.edu