bec/docs/source/user/usage.md

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## Client usage
### Starting the client
The client can be started by running
```bash
bec
```
### Interface
The client interface is based on the [IPython](https://ipython.org/) 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.
```{image} ../assets/tab-complete-devices.png
:align: center
:alt: tab completion for finding devices
:width: 300
```
```{hint}
`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
```ipython
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).
```python
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.
```python
scans.mv(dev.samx, 5, relative=False)
```
However, it can be made a blocking call by
```python
scans.mv(dev.samx, 5, relative=False).wait()
```
The same mv command can also be executed by calling the device method `move`
```python
dev.samx.move(5, relative=False)
```
````{note}
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.
```python
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.
```python
s = scans.line_scan(dev.samx, -5, 5, steps=10, exp_time=0.1, relative=False)
print(s.scan.data) # print the scan data
```