Automatic Shutter Control

In this section, the automatic shutter control in xpdAcq is introduced.

ShutterPreprocessor

The automatic shutter control is realized by the ShutterPreprocessor.

They are registered in the xrun.shutter_preprocessors list.

xrun.shutter_preprocessors

[<ShutterPreprocessor for detector>,
 <ShutterPreprocessor for detector1>,
 <ShutterPreprocessor for detector2>]

There is an one to one mapping between a shutter preprocessors to a detector and a many to one mapping between shutter preprocessors to the fast shutter.

Logic

When the ShutterPreProcessor finds that the detector is triggered to take a light frame (not labled by dark_group_prefix). Then, it will add the open and close shutter into the plan. The logic is shown in the peseudo code below.

if (shutter is closed currently):
    open the shutter
if (delay > 0):
    wait for seconds
trigger the detector
wait for the detector to finish counting
if (shutter is opened currently):
    close the shutter

Usage

By using the ShutterPreprocessor, users can use all the predefined plan in the bluesky.plans without worrying about the shutter control. For example, when users would like to collect one light frame, they just need to run the bluesky.plans.count.

xrun(0, bp.count([detector]))

INFO: Current filter status
INFO: flt1 : In
INFO: flt2 : In
INFO: flt3 : In
INFO: flt4 : In


Transient Scan ID: 1     Time: 2022-04-07 12:29:55
Persistent Unique Scan ID: '95cc5a91-2832-45b3-95df-630c8563414c'
New stream: 'dark'
New stream: 'primary'
+-----------+------------+
|   seq_num |       time |
+-----------+------------+
|         1 | 12:29:57.1 |
+-----------+------------+
generator count ['95cc5a91'] (scan num: 1)

('95cc5a91-2832-45b3-95df-630c8563414c',)

The shutter will open automatically before the collection and close after that.

Here is another example where users would like to collect several light frames at different temperatures.

xrun(0, bp.scan([detector], cryostream, 300, 500, 3))

INFO: Current filter status
INFO: flt1 : In
INFO: flt2 : In
INFO: flt3 : In
INFO: flt4 : In


Transient Scan ID: 2     Time: 2022-04-07 12:32:39
Persistent Unique Scan ID: '3e72d2a9-c6ef-4278-81da-db91bd28e35c'
New stream: 'dark'
New stream: 'primary'
+-----------+------------+-------------+
|   seq_num |       time | temperature |
+-----------+------------+-------------+
|         1 | 12:32:41.1 |     300.000 |
|         2 | 12:32:42.1 |     400.000 |
|         3 | 12:32:43.1 |     500.000 |
+-----------+------------+-------------+
generator scan ['3e72d2a9'] (scan num: 2)

('3e72d2a9-c6ef-4278-81da-db91bd28e35c',)

During the run, the shutter will open before the image collection and close after that at every temperature point. Users don’t need to worry that the shutter keeps open during the temperature ramping.

Enable and Disable

The ShutterPreprocessor can be disabled by calling disable. After disabled, it will do noting to the users’ plans.

xrun.shutter_preprocessors[0].disable()

It can be enabled again by calling enable.

xrun.shutter_preprocessors[0].enable()

ShutterConfig

The open and close state are defined in the ShutterConfig object.

This object is a private attribute of ShutterPreprocessor should be changed by users but the values in it can be reference to users when they are writing their own shutter control in the plan.

xrun.shutter_preprocessors[0]._shutter_config

ShutterConfig(shutter=FastShutter(name='shutter', value='closed', timestamp=1649349163.1470232), open_state='open', close_state='closed', delay=0.0)