bec/docs/source/user/usage.md

Client usage

Starting the client

The client can be started by running

bec

Interface

The client interface is based on the IPython interactive shell. As seen in the screenshot below, the prompt is prefixed with, e.g. demo [4/522] >>. The prefix contains the name of the current session (demo), the current cell number (4) and the next scan number (522).

Device access

Devices are grouped in dev. This allows users to use tab-completion for finding devices.

:align: center
:alt: tab completion for finding devices
:width: 300

`dev` is imported as a builtin. As a result, you can access `dev` from everywhere. `dev` itself is just an alias for `bec.device_manager.devices`.

Inspect a device

LamNI [2/522] >> dev.samx

Out[2]:
        Positioner(name=samx, enabled=True):
        --------------------
        Details:
            Status: enabled
            Last recorded value: {'value': 0, 'timestamp': 1671796007.547235}
            Device class: SynAxisOPAAS
            Acquisition group: motor
            Acquisition readoutPriority: monitored
            Device tags: ['user motors']
            User parameter: None
        --------------------
        Config:
            delay: 1
            labels: samx
            limits: [-50, 50]
            name: samx
            speed: 100
            tolerance: 0.01
            update_frequency: 400

Move a motor

There are two variants of device movements: updated move and move.

Updated move (umv)

A umv command blocks the command-line until the motor arrives at the target position (or an error occurs).

scans.umv(dev.samx, 5, relative=False)

Move (mv)

A mv command is non-blocking, i.e. it does not wait until the motor reaches the target position.

scans.mv(dev.samx, 5, relative=False)

However, it can be made a blocking call by

scans.mv(dev.samx, 5, relative=False).wait()

The same mv command can also be executed by calling the device method move

dev.samx.move(5, relative=False)

mv and umv can receive multiple devices, e.g.
```python
scans.umv(dev.samx, 5, dev.samy, 10, relative=False)
```

Run a scan

All currently available scans are accessible through scans., e.g.

s = scans.line_scan(dev.samx, -5, 5, steps=10, exp_time=0.1, relative=False)

Inspect the scan data

The return value of a scan is a python object of type ScanReport. All data is stored in <scan_report>.scan.data, e.g.

s = scans.line_scan(dev.samx, -5, 5, steps=10, exp_time=0.1, relative=False)
print(s.scan.data) # print the scan data