labyak

High-level wrappers around the LJM Python library for data acquisition and waveform or pattern generation with the LabJack T7. Labyak does not yet officially support the LabJack T4, but it should be mostly compatible.

To install with pip and git, run the following from the command line:

pip install git+http://github.com/robertfasano/labyak.git

Tutorial

See the Jupyter notebook "Examples.ipynb" for a runnable version.

Connecting to a device

  from labyak import LabJack
  labjack = LabJack(devid='470017907')

Analog I/O

Generate 1 V on channel DAC0 and measure it on ADC0:

  labjack.analog.AOut(0, 1)
  print(labjack.analog.AIn(0))

Generate -6 V with an LJTick-DAC on the FIO0-1 block and measure it with ADC1:

  labjack.analog.TDAC(0, -6)
  print(labjack.analog.AIn(1))

Digital I/O

Output a series of bits on FIO2 and read them on FIO3:

  write_bits = [0, 1, 1, 0, 1]
  read_bits = []

  for bit in write_bits:
      labjack.digital.DOut(2, bit)
      read_bits.append(labjack.digital.DIn(3))

  print(read_bits)

Temperature sensing

Measure a type J thermocouple using AIN2 and AIN3 for the positive and negative leads:

  labjack.temperature.configure(pos_ch=2, neg_ch=3, kind='J')
  labjack.temperature.TIn(2)

Waveform generation

Output a sine-wave from 0 to 5 V with 5 kHz frequency:

  import numpy as np
  f = 5e3                                       # frequency of waveform
  t = np.linspace(0, 1/f, 3000)                 # time axis of waveform
  V = 2.5*(1+np.sin(2*np.pi*f*t))               # sine wave

  labjack.waveform.start(t, V, channels = [1])  # start generation

Pattern generation

Generate a pattern on FIO3: high for 1 ms, low for 500 us, high for 2 ms, then low for 1 ms:

  period=4.5e-3
  sequence = {3: [(0, 1),         # start high
                  (1e-3, 0),      # switch to low at 1 ms
                  (1.5e-3, 1),    # switch to high at 1.5 ms
                  (3.5e-3, 0)]}   # switch to low at 3.5 ms

  labjack.pattern.start(sequence, period)