Skip to content
Flojoy Docs

MEASURE_VOLTAGE

Download Flojoy Studio to try this app
Query an instrument's measured output voltage, such as a DMM or power supply. Inputs ------ default: DataContainer Any DataContainer - likely connected to the output of the OPEN_SERIAL block. Params: connection : Serial The open serial connection with the instrument. Returns: out : Scalar|String The measured voltage as a Scalar or an exception error as a String.
Python Code
import traceback
from typing import Optional, cast

import serial
from flojoy import DataContainer, Scalar, SerialConnection, String, flojoy


@flojoy(deps={"pyserial": "3.5"}, inject_connection=True)
def MEASURE_VOLTAGE(
    connection: SerialConnection, default: Optional[DataContainer] = None
) -> Scalar | String:
    """Query an instrument's measured output voltage, such as a DMM or power supply.

    Inputs
    ------
    default: DataContainer
        Any DataContainer - likely connected to the output of the OPEN_SERIAL block.

    Parameters
    ----------
    connection: Serial
        The open serial connection with the instrument.

    Returns
    -------
    Scalar|String
        The measured voltage as a Scalar or an exception error as a String.
    """

    # Start serial communication with the instrument
    set = cast(serial.Serial, connection.get_handle())

    if set is None:
        raise ValueError("Serial communication is not open")

    CMD = "MEASURE:VOLTAGE:DC?\n\r"

    set.write(CMD.encode())

    resp = set.readline().decode()

    try:
        resp = float(resp.rstrip("\n"))
    except Exception:
        print(
            "Could not convert instrument response to a float", traceback.format_exc()
        )
        return String(resp)

    return Scalar(resp)

Find this Flojoy Block on GitHub

Videos

Control Agilent 34410A multimeter with Flojoy

Example App

Having problems with this example app? Join our Discord community and we will help you out!
React Flow mini map

This app queries an instrument for a voltage measurement once per second, then appends the result to a line graph.