labjack-ljm

library1.23.0pypypi✓ verified 85d ago

Python wrapper for the LabJack LJM library, used to control LabJack T4, T7, and T8 devices. Version 1.23.0 released in 2024. Active development with periodic updates.

data

pip install labjack-ljm

package ↗homepage ↗

INSTALL

IMPORT

SIG · LABJACK-LJM

labjack-ljm

datapythonv1.23.0

Install

1.7s avg

Import

15ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.23.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.010s · 18MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.7s · import 0.020s · 19MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

LJM

✓ import labjack.ljm as ljm

✗ from labjack import ljm

Incorrect import path; 'labjack.ljm' is the correct module.

LJM

✓ from labjack import ljm

Open a LabJack device, write to DAC0, read back, and close.

import labjack.ljm as ljm # Open first found LabJack device handle = ljm.openS("ANY", "ANY", "ANY") # returns handle info = ljm.getHandleInfo(handle) print(f"Opened a LabJack with device type: {info[0]} connection type: {info[1]} serial number: {info[2]} IP address: {info[3]} port: {info[4]} max bytes per MB: {info[5]}") # Write and read analog output ljm.eWriteName(handle, "DAC0", 2.5) # set DAC0 to 2.5V value = ljm.eReadName(handle, "DAC0") print(f"DAC0 value: {value}") ljm.close(handle)

Debug

Known issues

breakingLabJack T8 support introduced in LJM 1.20.0. Older LJM versions do not support T8 devices. Update accordingly.

fix

Upgrade to labjack-ljm >= 1.20.0 to use T8.

affects: <=1.19.0

breakingIn LJM 1.22.0, some function signatures changed (e.g., eWriteName now expects a float for analog outputs instead of int).

fix

Check the release notes for exact changes. Use floats for analog values.

affects: ==1.22.0

gotchaLJM requires the LabJack LJM library (shared library) to be installed on the system. pip install does not install the native library.

fix

Download and install LJM from LabJack's website (https://labjack.com/support/software/ljm).

affects: all

gotchaWhen opening devices, ensure only one instance of the device is open. Multiple handles to the same device can cause undefined behavior.

fix

Always close the handle after use with ljm.close(handle).

affects: all

deprecatedljm.listAll() is deprecated; use ljm.listAllS() instead.

fix

Replace ljm.listAll() with ljm.listAllS() in your code.

affects: >=1.22.0

Errors

Common errors & fixes

LJMError: LJM_ERROR_DEVICE_NOT_FOUND

Device not connected or LJM library not installed properly.

fix

Check USB/ethernet connection, ensure device is powered, and verify LJM native library is installed (run 'ljm_install' or see LabJack docs).

ImportError: No module named labjack.ljm

labjack-ljm Python package not installed or wrong import path.

fix

Install with 'pip install labjack-ljm' and import using 'import labjack.ljm as ljm'.

LJMError: LJM_ERROR_INVALID_HANDLE

Device handle is invalid (closed or never opened).

fix

Ensure handle is obtained from ljm.openS() and not closed before use.

LJMError: LJM_ERROR_LIBRARY_NOT_FOUND

Native LJM library (liblabjacklm.so or LabJackLM.dll) not found in system library path.

fix

Install the LJM native library from LabJack's website. On Linux, set LD_LIBRARY_PATH to the directory containing the library.

Upgrade

Version history

1.23.0latest on PyPI · released Dec 4, 2023

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

packagehttps://pypi.org/project/labjack-ljm/ ↗

homepagehttps://labjack.com/support/software/examples/ljm/python ↗