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dispenser

Festo Dispenser module containing Dispenser class and support functions.

Configurable class for dispensing applications. For now, this class assumes use of a Festo VAEM and PGVA for valve and pressure control respectively. Optional hooks in development for proportional pressure regulation using a VEAB connected to a Festo PLC and communicated with via socket using an API in the style of the Festo Easy Positioning API and integrated via support in the festo-applied-motion library. This will be separated into a dedicated pressure-control backend in a future revision.

Dispenser

Bases: DispenseMixin, PressureOverLiquidControl

Dispenser class for modular dispensing applications.

Driver for a Festo dispenser, e.g. VTOI, VTOE, VTOF. Currently, there are hard-coded dependencies on the festo-pgva and festo-vaem drivers for their respective hardware modules.

The dispense operation is provided by DispenseMixin.

Construction is handled entirely by PressureOverLiquidControl; component_id defaults to "dispenser_1" (derived from component_type).

Examples:

Load an instrument configuration and dispense 25 uL of water on channel 1:

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>>> import json
>>> from fluid_control import Dispenser
>>> with open("micro-dispenser-config.json") as fh:
...     config = json.load(fh)
>>> dispenser = Dispenser(config=config, component_id="micro-dispenser")
>>> dispenser.dispense({1: {"volume": 25.0, "liquid_class": "water"}})

Use as a context manager to guarantee the instrument is returned to a safe state on exit, even if an exception is raised:

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>>> with Dispenser(config=config, component_id="micro-dispenser") as dispenser:
...     dispenser.dispense({1: {"volume": 30.0, "liquid_class": "water"}})
Source code in src/fluid_control/dispenser.py 
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class Dispenser(DispenseMixin, PressureOverLiquidControl):
    """
    Dispenser class for modular dispensing applications.

    Driver for a Festo dispenser, e.g. VTOI, VTOE, VTOF.
    Currently, there are hard-coded dependencies on the festo-pgva and festo-vaem drivers
    for their respective hardware modules.

    The ``dispense`` operation is provided by [`DispenseMixin`][fluid_control.capabilities.DispenseMixin].

    Construction is handled entirely by
    [`PressureOverLiquidControl`][fluid_control.fluid_control.PressureOverLiquidControl]; ``component_id``
    defaults to ``"dispenser_1"`` (derived from ``component_type``).

    Examples:
        Load an instrument configuration and dispense 25 uL of water on channel 1:

        >>> import json
        >>> from fluid_control import Dispenser
        >>> with open("micro-dispenser-config.json") as fh:
        ...     config = json.load(fh)
        >>> dispenser = Dispenser(config=config, component_id="micro-dispenser")
        >>> dispenser.dispense({1: {"volume": 25.0, "liquid_class": "water"}})

        Use as a context manager to guarantee the instrument is returned to a
        safe state on exit, even if an exception is raised:

        >>> with Dispenser(config=config, component_id="micro-dispenser") as dispenser:
        ...     dispenser.dispense({1: {"volume": 30.0, "liquid_class": "water"}})

    """

    component_type: str = "dispenser"