ATTACH_ANALOG_INPUT_CURRENT

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Attach channel(s) to a task to measure current. **Compatibility:** Compatible with National Instruments devices that utilize NI-DAQmx. Tested with an NI-9203 module. 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 attach the channel(s) to. cDAQ_start_channel : NIDAQmxDevice The device and channel to read from. Flojoy will register this address as a connection. cDAQ_end_channel : NIDAQmxDevice To read from only one channel, set this to the same as `cDAQ_start_channel`. To read from multiple channels, set this to the last channel you want to read from. min_val : float Specifies in **units** the minimum value you expect to measure (default is -0.01). max_val : float Specifies in **units** the maximum value you expect to measure (default is 0.01). units : Literal The units to use to return current measurements (default is "AMPS"). Returns: out : Optional[DataContainer] This block does not return any meaningful data; it is designed for creating a task to measure current.

Python Code

from flojoy import flojoy, DataContainer, NIDAQmxDevice, DeviceConnectionManager
from typing import Optional, Literal
import nidaqmx


@flojoy(deps={"nidaqmx": "0.9.0"})
def ATTACH_ANALOG_INPUT_CURRENT(
    task_name: str,
    cDAQ_start_channel: NIDAQmxDevice,
    cDAQ_end_channel: NIDAQmxDevice,
    min_val: float = -0.01,
    max_val: float = 0.01,
    units: Literal["AMPS"] = "AMPS",
    default: Optional[DataContainer] = None,
) -> Optional[DataContainer]:
    """Attach channel(s) to a task to measure current.

    **Compatibility:**
    Compatible with National Instruments devices that utilize NI-DAQmx. Tested with an NI-9203 module.

    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 attach the channel(s) to.
    cDAQ_start_channel : NIDAQmxDevice
        The device and channel to read from. Flojoy will register this address as a connection.
    cDAQ_end_channel : NIDAQmxDevice
        To read from only one channel, set this to the same as `cDAQ_start_channel`. To read from multiple channels, set this to the last channel you want to read from.
    min_val : float, optional
        Specifies in **units** the minimum value you expect to measure (default is -0.01).
    max_val : float, optional
        Specifies in **units** the maximum value you expect to measure (default is 0.01).
    units : Literal, optional
        The units to use to return current measurements (default is "AMPS").

    Returns
    -------
    Optional[DataContainer]
        This block does not return any meaningful data; it is designed for creating a task to measure current.
    """
    # Check if task already exists
    task = DeviceConnectionManager.get_connection(task_name).get_handle()

    # Attach the requested channel(s) to the task
    name, address = cDAQ_start_channel.get_id().split("/")
    if cDAQ_end_channel:
        _, address_end = cDAQ_end_channel.get_id().split("/")
        address = f"{address}:{address_end[2:]}"
    physical_channels = f"{name}/{address}"

    units = (
        nidaqmx.constants.CurrentUnits.AMPS
    )  # TODO: Support TEDS info associated with the channel and custom scale

    task.ai_channels.add_ai_current_chan(
        physical_channels, min_val=min_val, max_val=max_val, units=units
    )  # TODO: Add shunt resistor option

    return None

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Example App

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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.