Adding Devices to an Instrument#

Every new instrument comes pre-loaded with a simulated motor and a detector. To add a new device to your instrument startup, a couple of steps must be taken. For the purpose of this tutorial we assume you have already used BITS to create an instrument called new_instrument.

  1. Create a new device class in the devices folder

from ophyd import Device, EpicsMotor
from ophyd import Component as Cpt

class StageXY(Device):
    x = Cpt(EpicsMotor, ':X')
    y = Cpt(EpicsMotor, ':Y')

  1. Add the new device class to the device my_instrument/devices/__init__.py file

If you want to use a device from an external package, make sure to add it to the my_instrument/devices/__init__.py file in the device folder of your instrument.

from .stage_xy import StageXY ##import from your own devices folder

  1. Add the new device to the instrument configuration file

Depending on if the device can only function on the aps network or not add it to the device.yml file or the devices_aps_only.yml file.

new_instrument.devices.StageXY:
- name: stage
  prefix: BITS
  labels: ["motors"]

You can also add a device from an external package to the devices.yml file.

apstools.synApps.Optics2Slit2D_HV:
- name: slit1
  prefix: ioc:Slit1
  labels: ["slits"]

  1. Make sure all your device files are loaded on the iconfig.yml file.

DEVICES_FILES:
  - devices.yml
APS_DEVICES_FILES:
  - devices_aps_only.yml

Note that the devices.yml file is loaded by default and the devices_aps_only.yml file is only loaded if the device is on the APS network.

Tip

All kwargs of your device can be specified in the yaml file making it easy to resuse classes.

Tip

You can add any number of device files inside the iconfig file used by your instrument startup.py file. Just add another entry to the list.

### Local OPHYD Device Control Yaml
DEVICES_FILES:
  - devices.yml ## standard device file
  - devices_2.yml ## another device file
APS_DEVICES_FILES:
  - devices_aps_only.yml ## APS only device file
  - devices_aps_only_2.yml ## another APS only device file

Tip

APSTOOLS has a lot of devices commonly used at the APS. Consider first checking the package and overwriting the device class to fit your needs before creating a new device.

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