READ_INPUT_STREAM_INTO_BUFFER

Reads raw samples from the specified task or virtual channels into the provided buffer. Raw samples constitute the internal representation of samples in a device, read directly from the device or buffer without scaling or reordering. **Compatibility:** Compatible with National Instruments devices that utilize NI-DAQmx. This block is designed for use with Windows and Linux systems due to NI driver availability. Ensure you have installed the NI-DAQmx runtime from https://www.ni.com/en/support/downloads/drivers/download.ni-daq-mx.html. Params: task_name : str The name of the task to read from. buffer : Vector Reads raw samples from the specified task or virtual channels into this pre-allocated buffer. Ensure that the buffer size is appropriate for the expected number of samples and the raw sample size. default : Optional[DataContainer] Special parameter used by Flojoy to connect blocks together. Returns: out : Vector Returns data in an interleaved or non-interleaved 1D array, depending on the raw ordering of the device. Refer to your device documentation for more information.

Python Code

from flojoy import flojoy, DataContainer, DeviceConnectionManager, Vector
from typing import Optional


@flojoy(deps={"nidaqmx": "0.9.0"})
def READ_INPUT_STREAM_INTO_BUFFER(
    task_name: str,
    buffer: Vector,
    default: Optional[DataContainer] = None,
) -> Vector:
    """Reads raw samples from the specified task or virtual channels into the provided buffer.

    Raw samples constitute the internal representation of samples in a device, read directly from the device or buffer without scaling or reordering.

    **Compatibility:**
    Compatible with National Instruments devices that utilize NI-DAQmx.

    This block is designed for use with Windows and Linux systems due to NI driver availability. Ensure you have installed the NI-DAQmx runtime from https://www.ni.com/en/support/downloads/drivers/download.ni-daq-mx.html.

    Parameters
    ----------
    task_name : str
        The name of the task to read from.
    buffer : Vector
        Reads raw samples from the specified task or virtual channels into this pre-allocated buffer.
        Ensure that the buffer size is appropriate for the expected number of samples and the raw sample size.
    default : Optional[DataContainer], optional
        Special parameter used by Flojoy to connect blocks together.

    Returns
    -------
    Vector
        Returns data in an interleaved or non-interleaved 1D array, depending on the raw ordering of the device. Refer to your device documentation for more information.
    """

    task = DeviceConnectionManager.get_connection(task_name).get_handle()

    task.in_stream.readinto(buffer.v)

    return buffer

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Example

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Download this Flojoy App

This app shows how to use input stream blocks for with National Instruments Compact DAQ module.

Blocks used:

• CREATE_TASK_ANALOG_INPUT_CURRENT
• CONFIG_INPUT_STREAM
• READ_INPUT_STREAM
• READ_INPUT_STREAM_INTO_BUFFER
• 2x LINE
• PRINT_DATACONTAINER
• TEXT_VIEW
• TIMER
• LOOP

The blocks were connected as shown, and the app was run. The result displayed the first 100 samples from an analog module in the first plot and constantly updated the second plot with the latest data from the device buffer.