This library provides a Python wrapper for reading 4-20mA signals using LabJack's T7 data logger.
By Chris Arcadia
Created on 2021/05/30.
- LabJack's LJM driver and Python wrapper
- Python 2.6, 2.7 or 3.x**
- LabJack T7 or T4 for reading the analog signals
- sensor that is transmitting the 4-20mA signals (such as a pH meter)
- CPU (Windows, macOS, or Linux) with USB 3
- get and install the LJM Library (I installed LabJack-2019-05-20.exe)
- install the Python package laback-ljm (using PIP:
pip install labjack-ljm
). - try running an example script (such as simple_log.py or one of the others on GitHub)
More detailed instructions can be found on LabJack's Python for LJM page.
This library has been tested on a Windows device, but since the Python wrapper for LabJack works on Windows/Mac/Linux, this should work across platforms. The test setup was running Python 3.6.1 from Anaconda 3 (4.4.0).
If you run the class' __main__
script, you will get the following output:
LabJack: System initialized.
LabJack:
Opened a LabJack with Device type: 7, Connection type: 1,
Serial number: 470014465, IP address: 0.0.0.0, Port: 0,
Max bytes per MB: 64
Start time is: 2021/06/18 01:43:15PM
Reading AIN0 10 times and saving data to the file:
C:\Users\ChrisArcadia\__temporary__\2021_06_18-01_43_15PM-AIN0.csv
AIN0 reading: pH of 3.645954 as -3.489676 V, duration: 100455.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.704948 as -3.518485 V, duration: 100021.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.679573 as -3.506093 V, duration: 100147.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.668097 as -3.500489 V, duration: 99839.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.644823 as -3.489123 V, duration: 100063.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.631569 as -3.482651 V, duration: 99952.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.605708 as -3.470022 V, duration: 100085.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.700908 as -3.516512 V, duration: 99926.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.697190 as -3.514696 V, duration: 100042.0 ms, skipped intervals: 0
AIN0 reading: pH of 3.676987 as -3.504830 V, duration: 100044.0 ms, skipped intervals: 0
Finished!