LabJack-Driver

This is a driver for the LabJack T7. Currently, this hardware only reads the analog inputs of the LabJack over Ethernet.

Capabilities

• Set Voltage Range: Supports setting the voltage range for analog input channels (AIN) to ±10V, ±1V, ±0.1V, or ±0.01V.
• Single-Ended (GND-Referenced) Measurements: Perform single-ended readings, where the input is referenced to GND.
• Differential Measurements: Perform differential readings, where one analog input is referenced to another input (e.g., AIN2 is referenced to AIN3).
• The structure of this library is identical to that of ADAM-driver and NIDAQ-driver, allowing easy integration into nexo and ScriptSynth.

Requirements

pip install LabJackPython ljm

Documentation

Differential vs. Single-Ended Measurements

• Single-Ended (GND-Referenced) Measurements:

  • In a single-ended measurement, the analog input is referenced to GND (ground). For example, reading AIN0 with a GND reference means the LabJack measures the voltage difference between AIN0 and GND.
  • To configure a channel for single-ended mode, set the AIN#_NEGATIVE_CH to 199 (which corresponds to GND).

• Differential Measurements:

  • In a differential measurement, the voltage difference between two analog inputs is measured. For example, you can measure AIN2 referenced to AIN3 by setting the AIN2_NEGATIVE_CH to 3 (AIN3).

  • This mode is useful when you want to measure signals that are not referenced to GND but instead to another input channel.

  • To configure a channel for differential mode, set the AIN#_NEGATIVE_CH to the index of the negative channel (e.g., AIN2_NEGATIVE_CH = 3 for differential measurement between AIN2 and AIN3).

  • LabJack T7 Differential Input Rules:

  • Differential channels must be configured in adjacent even/odd pairs. For example:

    • AIN0 (positive) can use AIN1 (negative).
    • AIN2 (positive) can use AIN3 (negative).
    • AIN4 (positive) can use AIN5 (negative), and so on.

  • You can only assign even-numbered channels (AIN0, AIN2, AIN4, etc.) as the positive channel for differential measurements. Their corresponding odd-numbered neighbors (AIN1, AIN3, AIN5, etc.) will be the negative channel.

Example Configuration:

• Single-Ended Reading (AIN0-GND):

  labjack.set_range(0, "10V")
  labjack.configure_measurement_type(0, measurement_type="single-ended")

• Differential Reading (AIN0-GND):

  labjack.set_range(2, "10V")
  labjack.configure_measurement_type(2, measurement_type="differential", differential_negative_channel=3)

Example Usage

from LabjackClient import LabJackT7Driver

# LabJack IP Address
LABJACK_IP = "172.18.120.132"

# Initialize the LabJackT7Driver with the IP address
client = LabJackT7Driver(ip_address=LABJACK_IP)

try:
    # Configure the voltage range for AIN0 to ±10V and set the negative channel to GND (single-ended)
    client.set_range(0, "10V")
    client.configure_measurement_type(0, measurement_type="single-ended")

    # Configure AIN2 to take a differential reading using AIN3 as the negative channel
    client.set_range(2, "10V")
    client.configure_measurement_type(2, measurement_type="differential", differential_negative_channel=3)

    # Read analog input values from the first 4 channels
    analog_values = client.read_samples([f"AIN{i}" for i in range(4)])
    print(analog_values)

except Exception as e:
    print(f"Error: {e}")

finally:
    client.close()

Setup

The Labjack device must be connected via Ethernet; the IP should be automatically assigned, but you will need to find the IP address. To do this, download Kipling, the official configuration utility. After running this, you will find something like this:

The Ethernet IP is shown in the configuration utility. Write down the IP address.