labjack-unified

Classes with unified methods to interact with LabJack DAQ devices U3, U6 and T7.

About

Three classes are available (LabJackU3, LabJackU6, and LabJackT7) which have the common methods listed below. They should cover the majority of LabJack applications. There are also device specific methods as well (see each class for more details).

Method	Description
close	Closes the LabJack device
display_info	Displays summary info about the device
set_digital	Writes digital value to specified port(s)
get_digital	Reads digital value from specified port(s)
set_analog	Writes analog value to specified port(s)
get_analog	Reads analog value from specified port(s)
get_labjacktemp	Gets ambient temperature from internal sensor
set_stream	Sets LabJack configuration for data streaming
get_stream	Gets streaming data
stop_stream	Stops data streaming
set_PWM	Sets LabJack configuration for PWM output
set_dutycycle	Sets duty cycle of PWM output
set_quadrature	Sets LabJack configuration for encoder A-B-Z input
get_counter	Gets edge count from encoder A-B signals
reset_counter	Resets edge counter

Installation

>>> py -m pip install labjack-unified

Installing labjack-unified will install its dependencies: LabJackPython and labjack-ljm. Plotly will also be installed so graphs can be displayed when running the examples.

Examples

Nine examples are available, with four of them requiring only a pair of wires to be executed successfully. Below is the code for some analog I/O testing:

""" lj_io_analog.py

Uses analog input and output channels.

This example shows how to use analog inputs and outputs in a data acquisition
loop. Accurate time execution of output events can be achieved by the use of a
timer logic in the loop. The voltage measurements are executed as fast as
possible. The main latency source is the LabJack I/O times.

Setup:
   Connect DAC0 to AIN0
   Connect DAC1 to AIN1

The LabJack unified methods in this example are:
   set_analog ....... Writes analog value to specified port(s)
   get_analog ....... Reads analog value from specified port(s)
   close ............ Closes the LabJack device

"""
import time
import numpy as np
from labjack_unified.utils import plot_line
from labjack_unified.devices import LabJackU3, LabJackU6, LabJackT7

# To use a LabJack U6 or a T7, change the device name
# from LabJackU3 below to either LabJackU6 or LabJackT7
lj = LabJackU3()

# Assigning parameters
tstep = 0.5 # Interval between step changes (s)
t = [] # Output time array
v1 = [] # Output sampled voltage 1 array
v2 = [] # Output sampled voltage 2 array

# Initializing timers and starting main clock
tprev = 0
tcurr = 0
tstart = time.perf_counter()
# Executing acquisition loop
print('Running code for 5 seconds ...')
while tcurr <= 5:
   # Updating analog output every `tstep` seconds
   # with random voltages between 0 and 5 V
   if (np.floor(tcurr/tstep) - np.floor(tprev/tstep)) == 1:
      lj.set_analog('DAC0', 5*np.random.rand())
      lj.set_analog('DAC1', 5*np.random.rand())
   # Updating previous time and getting current time (s)
   tprev = tcurr
   tcurr = time.perf_counter() - tstart
   # Acquiring analog data as fast as possible
   # and appending values to output arrays
   t.append(tcurr)
   v1.append(lj.get_analog('AIN0'))
   v2.append(lj.get_analog('AIN1'))
print('Done.')
# Closing the device
lj.close()
del lj

Warning

Due to their implementation, the classes LabJackU3 and LabJackU6 only work on a Windows platform.

Issues and questions

If you have a feature request, a bug report, or even a question, please open an issue on GitHub.