Migrate from LabVIEW to Python

LabVIEW is powerful, but it comes with $3,000-5,000/seat licensing, Windows-only deployment, and binary files that don't version-control well. Python gives you the same instrument control capabilities with zero license cost, cross-platform support, and native Git integration. This guide maps LabVIEW concepts to Python equivalents and shows you how to rebuild your test system with the TofuPilot Framework or OpenHTF.

Why Teams Migrate

LabVIEW to Python Concept Map

Step 1: Set Up Your Python Environment

python -m venv venvsource venv/bin/activate    # Linux/macOS# venv\Scripts\activate     # Windowspip install pyvisa pyvisa-py

Then install the TofuPilot CLI, which runs procedures and streams results:

curl -fsSL https://www.tofupilot.app/install | sh

tofupilot run ./procedure.yaml executes a procedure on your machine without an account, so you can validate a migrated test before connecting anything.

Step 2: Convert SubVIs to Python Functions

A LabVIEW SubVI that reads voltage from a DMM becomes a Python function:

def measure_voltage(channel: int) -> float:    """Equivalent of a LabVIEW SubVI that reads voltage from a DMM.    In LabVIEW: SubVI with channel input (I32) and voltage output (DBL).    In Python: function with type hints.    """    readings = {1: 3.31, 2: 5.02, 3: 1.81}  # Replace with real reads    return readings.get(channel, 0.0)# Call it like you'd wire a SubVIrail_3v3 = measure_voltage(1)rail_5v0 = measure_voltage(2)

The function signature replaces the connector pane. Type hints (int, float) replace the LabVIEW data types.

Step 3: Replace the Error Cluster

LabVIEW uses an error cluster (status, code, source) wired through every VI. Python uses exceptions.

class InstrumentError(Exception):    """Replaces LabVIEW error cluster for instrument errors."""    def __init__(self, code: int, source: str, message: str):        self.code = code        self.source = source        super().__init__(f"[{code}] {source}: {message}")# LabVIEW: check error cluster at every node# Python: try/except catches errors from anywhere in the blocktry:    voltage = measure_voltage(1)    if voltage < 0:        raise InstrumentError(1001, "DMM", "Negative voltage reading")except InstrumentError as e:    print(f"Instrument error: {e}")    # Handle or re-raise

This is cleaner than wiring error clusters through every node. Exceptions propagate automatically until caught.

Step 4: Stop Building the Sequencer

LabVIEW state machines use a while loop plus a case structure, and most teams hand-roll a sequencer on top. You do not need to port that. Both Python hardware frameworks provide sequencing, limits and pass/fail evaluation.

The TofuPilot Framework

The procedure YAML replaces the state machine: it declares the order, the measurements and the limits. Phases are plain Python functions, and instrument drivers become plugs.

class Multimeter:    """Replaces the LabVIEW instrument driver VIs.    __init__ = opening a VISA session in LabVIEW    methods  = the SubVIs for each measurement    close    = closing the session    """    def __init__(self):        self._voltages = iter([3.31, 5.02])        # Replace with:        # import pyvisa        # rm = pyvisa.ResourceManager("@py")        # self.instr = rm.open_resource("TCPIP::192.168.1.100::INSTR")    def read_voltage(self) -> float:        return next(self._voltages)        # Replace with: return float(self.instr.query(":MEAS:VOLT:DC?"))    def close(self):        pass        # Replace with: self.instr.close()

def power_rails(measurements, dmm):    """Replaces a LabVIEW sequence of Numeric Limit Tests."""    measurements.rail_3v3 = dmm.read_voltage()    measurements.rail_5v0 = dmm.read_voltage()

name: PCBA Functional Testversion: 1.0.0unit:  serial_number:    default_value: "PCBA000001"  part_number:    default_value: "PCBA-100"plugs:  - name: dmm    python: plugs.dmm:Multimetermain:  - name: Power Rails    python: phases.power_rails    measurements:      - name: Rail 3V3        unit: V        validators:          - operator: ">="            expected_value: 3.2          - operator: "<="            expected_value: 3.4      - name: Rail 5V0        unit: V        validators:          - operator: ">="            expected_value: 4.8          - operator: "<="            expected_value: 5.2

Each validators block is the direct equivalent of a LabVIEW Numeric Limit Test, stored as data rather than buried in wires. The plug is injected into the phase by parameter name.

Two things migrating teams usually want, which the framework provides without extra work:

• The front panel. Operator inputs, checklists, images, sliders and progress bars are declared in the procedure, so you do not rebuild a UI.
• Parallel sequence execution. If your LabVIEW system tested several UUTs at once, declare fixture slots and the engine runs them concurrently:

execution:  slots:    - name: Slot 1    - name: Slot 2    - name: Slot 3    - name: Slot 4

Each slot uploads its own run, with its own unit and outcome.

OpenHTF

If you prefer everything in Python with no separate YAML layer, OpenHTF attaches measurements and plugs to phase functions with decorators.

import openhtf as htffrom openhtf.plugs import BasePlugfrom openhtf.util import unitsfrom tofupilot.openhtf import uploadclass InstrumentPlug(BasePlug):    """Replaces LabVIEW instrument driver VIs.    setUp = equivalent of opening a VISA session in LabVIEW    methods = equivalent of SubVIs for each measurement    tearDown = equivalent of closing the session    """    def setUp(self):        self._voltages = iter([3.31, 5.02])        # Replace with: rm = pyvisa.ResourceManager("@py")        # self.instr = rm.open_resource("TCPIP::192.168.1.100::INSTR")    def read_voltage(self) -> float:        return next(self._voltages)        # Replace with: return float(self.instr.query(":MEAS:VOLT:DC?"))    def tearDown(self):        pass        # Replace with: self.instr.close()@htf.measures(    htf.Measurement("rail_3v3")    .in_range(3.2, 3.4)    .with_units(units.VOLT)    .doc("3.3V rail"),    htf.Measurement("rail_5v0")    .in_range(4.8, 5.2)    .with_units(units.VOLT)    .doc("5.0V rail"),)@htf.plug(instr=InstrumentPlug)def test_power_rails(test, instr):    """Replaces a LabVIEW test sequence with Numeric Limit Tests."""    test.measurements.rail_3v3 = instr.read_voltage()    test.measurements.rail_5v0 = instr.read_voltage()def main():    test = htf.Test(        test_power_rails,        procedure_id="FCT-001",        part_number="PCBA-100",    )    test.add_output_callbacks(upload())    test.execute(test_start=lambda: input("Scan serial number: "))if __name__ == "__main__":    main()

Install with pip install "tofupilot[openhtf]", or skip the callback and run the suite with tofupilot run.

Which one

Both run natively on the TofuPilot CLI and upload to the same dashboard.

Step 5: Replace TDMS with TofuPilot

LabVIEW writes test data to TDMS files. You then need to build your own analytics tools to read them. TofuPilot replaces this entire pipeline.

tofupilot run ./procedure.yaml --upload

Migration Checklist

Common Gotchas