Closed qzhang234 closed 1 year ago
The generic solution when adding EPICS configuration PVs to an ophyd device is to add them as a EpicsSignal or EpicsSignalWithRBV. Even though you only plan to set them once, you might want to record their current setting as part of data acquisition.
Example
An area detector CAM has ad:cam1:NewFeature
and ad:cam1:NewFeature_RBV
PVs which describe a new configuration feature.
ad:
prefix will be specified when the detector object is created.cam1:
prefix, so the remaining PV parts should be used with this component attribute.kind="config"
since this configures the camera._RBV
, then use EpicsSignalWithRBV
.Add this line to the ophyd class that provides the cam for this detector (it will connect with both PVs):
new_feature = Component(EpicsSignalWithRBV, "NewFeature", kind="config")
@qzhang234 How is the energy threshold set (without bluesky)?
Pete, This is now set manually by the choice of the staff for each experiment. Suresh
From: Pete R Jemian @.> Date: Wednesday, December 21, 2022 at 8:49 AM To: aps-8id-dys/bluesky @.> Cc: Subscribed @.***> Subject: Re: [aps-8id-dys/bluesky] lambda.cam is missing energy threshold (Issue #5)
@qzhang234https://github.com/qzhang234 How is the energy threshold set (without bluesky)?
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Not quite the kind of answer I was expecting but it is helpful to know that the configuration may be used by users occasionally, not just during initial setup.
By what means is the energy threshold changed?
In a presentation just now, I saw this is a PV in the EPICS IOC's cam module with label Energy Threshold. What is the PV?
Also, there is a Dual Threshold feature just below Energy Threshold. Will this also be used?
Pete,
Typically: Threshold should be set to half of the x-ray energy being used, this is the reason that this should be decided by the staff manually. Sometimes, threshold is tweaked to a value different than ½ of x-rays. Dual threshold is an option that one could use, it runs at ½ the max frame rate. XPCS has not used it so far but might use it after apsu.
Energy Threshold PV: cam1:EnergyThreshold (always active) Dual threshold mode switch: cam1:DualMode (On/Off) Upper threshold PV: DualThreshold
Suresh
From: Pete R Jemian @.> Date: Wednesday, December 21, 2022 at 10:06 AM To: aps-8id-dys/bluesky @.> Cc: Narayanan, Suresh @.>, Comment @.> Subject: Re: [aps-8id-dys/bluesky] lambda.cam is missing energy threshold (Issue #5)
Not quite the kind of answer I was expecting. By what means is the energy threshold changed?
In a presentation just now, I saw this is a PV in the EPICS IOC's cam module with label Energy Threshold. What is the PV?
Also, there is a Dual Threshold feature just below Energy Threshold. Will this also be used?
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Ophyd controls for these PVs can be created, through which you can adjust their settings in the IOC. Bluesky does not use these, but rather makes them available for you to control.
63 lambda2M.cam.energy_threshold 1.0 2023-03-01 16:43:40.296113
64 lambda2M.cam.dual_mode Single 2023-03-01 16:43:40.320103
65 lambda2M.cam.dual_threshold 1.5 2023-03-01 16:43:40.347675
What is the generic solution for problems like these? Adding the attribute to the detector class or changing it in Bluesky plan using
pyepics
?