U12 | LabJack

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U12 U12-NTH U12-PH

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USB DAQ device with 8 analog inputs(12-bit), 2 analog outputs(10-bit), 20 digital I/O, and a 32-bit counter.

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In Stock

USB Multifunction DAQ

The U12 is the original LabJack. The device is solid - the firmware hasn't changed in a decade, and it has a very long service record of reliability and customer satisfaction - all with an attractive price point. It can be used for measurement and control within simple analog and digital systems. We continue to produce and sell U12s because a large number of our customers have integrated them successfully into other products.

New applications should consider the U3 family over the U12 because the U3 is faster, more flexible, and is compatible with our wide array of LJTick accessories.

Notice: macOS 10.15.4+ are not supported for the U12

The U12 USB interface relies on Apple kernel extensions, which were deprecated in macOS 10.15.4.

Product Highlights

Analog Inputs:

The LabJack U12 has 8 screw terminals for analog input signals (AI0-AI7). These can be configured individually as 8 single-ended channels, 4 differential channels, or combinations in between. Each input has a ±10 volt input range, 12-bit resolution, and an input bias current of ±90 microamps. Differential channels can make use of the low noise precision PGA to provide gains up to 20.

The LabJack U12 is capable of both software and hardware timed acquisition. When using software timed acquisition (also called command/response), the PC sends a command to the LabJack, and it responds with data. This mode can acquire 4 channels at up to 50 samples/second per channel, or 8 channels at up to 25 samples/second per channel. When using hardware timed acquisition, the PC sends a command to the LabJack telling it to start a burst or stream mode acquisition. Both burst and stream mode take advantage of the LabJack's precision timing crystal and high-speed sample buffer. In burst mode, up to 4,096 samples will be acquired from 1-4 channels at up to 8,192 samples/second and stored in the buffer. After the acquisition is complete, the data is transferred to the PC. A hardware trigger can be configured for burst mode that starts the acquisition when a digital input changes state. In stream mode, data is acquired from 1-4 channels at up to 1,200 samples/second and stored in the LabJack buffer. Simultaneously, the data is transferred from the LabJack buffer to the PC buffer, allowing the data to be streamed to disk continuously. Click here for more info on data rates.

Analog Outputs:

The LabJack U12 has 2 screw terminals for analog output signals (AO0 & AO1). Each analog output can be set to a voltage between 0 and the supply voltage (+5 volts nominal) with 10-bits of resolution. The analog outputs are controlled in command/response mode at up to 50 Hz per channel.

Digital I/O:

The LabJack U12 has 20 digital I/O channels which can be individually configured as input or output.

Connections to 4 of the digital I/O are made with the built-in screw terminals (IO0-IO3). These 4 channels have built-in overvoltage/short-circuit protection. As inputs or outputs, they are controlled/read in command/response mode at up to 50 Hz per bit. As inputs only, they can be read with the high-speed burst and stream modes.

The remaining 16 digital I/O are accessed through the DB-25 connector and controlled/read in command/response mode at up to 50 Hz per bit. These channels can sink or source up to 25 mA each (total sink or source current of 200 mA max for all 16), allowing direct interface to many relays.


There is one 32-bit counter available on the LabJack U12 (screw terminal CNT), capable of counting frequencies up to 1 MHz. The counter is read in command/response mode at up to 50 Hz or up to 300 Hz in hardware timed stream mode.

Watchdog Timer Function for Unattended Operation:

The LabJack U12 also has a watchdog timer function available which can change the states of digital I/O if the LabJack does not successfully communicate with the PC within a specified timeout period. This function could be used to reboot the PC allowing for reliable unattended operation.

Portable Data Acquisition and Control:

When used with a notebook PC, the LabJack U12 becomes a convenient portable data acquisition and control system. The watchdog timer function allows the development of a system which has the reliability of a datalogger with the power of a PC. The low-power design of the LabJack U12 allows it to draw all it's power from the USB port. Also, no UPS is needed when using a LabJack U12 with a notebook PC. In the event of power loss, both the LabJack and the notebook will continue to operate.

High Channel Count Applications:

By using USB hubs, up to 80 LabJacks can be connected to a single USB host, providing an inexpensive solution for low-speed high channel count applications.

Hardware Overview

Technical Specifications

  • 8 Single-Ended, 4 Differential 12-Bit Analog Inputs
  • ±10 Volt Analog Input Range
  • PGA with Gains of 1, 2, 4, 5, 8, 10, 16, or 20 V/V
  • Up to 8 ksamples/Sec (Burst) or 1.2 ksamples/Second (Stream)
  • Supports Software or Hardware Timed Acquisition
  • 2 Analog Outputs
  • 20 Digital I/O (Up to 50 Hz per I/O)
  • 32-Bit Counter
  • Watchdog Timer Function
  • USB 2.0/1.1 Low Speed Interface (Data Rate Information)
  • Connect Up to 80 LabJacks to One USB Host
  • Complete Software Control, No Jumpers or Switches
  • No Power Supply Needed
  • Includes Sample Applications and Drivers
  • Includes LabVIEW VIs
  • Works with Windows 98SE, ME, 2000, XP, or Vista
  • Includes Cable and Screwdriver
  • Money Back Guarantee
  • Approximately 4" x 6" x 1"
  • Rated for Industrial Temperature Range
  • OEM Board-Only Versions Available
  • Complete specifications in Appendix A of User's Guide

For more technical specifications look at the U12's datasheet.

Product Variations

OEM Versions (U12-PH and U12-NTH)

There are 2 OEM board-only versions of the U12 available for customers interested in designing the U12 into another product.

LabJack U12-PH (OEM Version): This -PH board has pin-headers installed (component side) instead of screw-terminals, and the LED is mounted on the component side.

LabJack U12-NTH (OEM Version): This -NTH board does not have any through-hole components installed (screw-terminals, pin-headers, LED, USB connector, and DB25 connector).

The OEM versions do not include anything besides the board itself. Dimensional drawings and software are available on the U12 downloads page.

Other Highlights

Free Example Application Software:

Includes various example applications, including LJlogger and LJscope. LJlogger provides datalogger type functionality. It reads all inputs, controls all outputs, writes real time data to disk, and sends email when events are triggered. LJscope is a simple virtual oscilloscope program. This software is free and can be downloaded from the U12 Library page for evaluation.

Free Driver Software:

Drivers are provided as a DLL which can be called from most programming languages. Also included are an ActiveX wrapper and LabVIEW VIs which call all the functions in the DLL. Most driver functions have a demo input, so applications can be developed and tested without hardware.

Includes Everything for Out-of-the-Box Operation:

Everything needed (software, screwdriver, and USB cable) is included with the LabJack U12. Installation is very simple and takes just a few minutes:

  1. Connect to the USB port on a PC running Windows 98SE/ME/2000/XP/Vista/7/8 using the included cable. The low-level drivers, which come with Windows, will be installed automatically.
  2. Run the LabJack installation program to install the high-level drivers and example applications.

Optional Accessories

The LabJack U12 comes complete, but we do offer a few optional accessories.

The CB25 provides screw-terminal connections and short-circuit/overvoltage protection for the 16 I/O which are accessed through the DB25 connector.

The RB16 provides sockets for industry standard miniature I/O modules (solid state relays).

The EI-1022 is an inexpensive and easy to use temperature probe.

The EI-1040 is a single-supply dual instrumentation amp that provides high impedance and high gain.

Satisfaction Guaranteed

Everything we sell has a 30-day money back guarantee. If, for any reason, you are not satisfied with a product, contact us to arrange your choice of a refund or replacement. In addition, the LabJack U12 is covered by a 1-year limited warranty.

Technical Support

All LabJacks include lifetime technical support. Support resources include forum, FAQs, email, and telephone.

Drivers and Examples:

The U12 Quickstart page describes software options. LabJack provides drivers for the three major operating systems, and examples for most common programming languages.

Package Contents

Package Contents (Non-OEM)

  • U12 unit itself in red enclosure
  • USB cable (6 ft / 1.8 m)
  • Screwdriver
  • Other package details: No software CD included. Download the software from labjack.com.
  • Retail packing (Package) size: 8" x 5.5" x 2"
  • Retail packing (Package) wt: 1 lb


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Support Resources

Getting Started

U12 USB DAQ Software and Driver

Install Software

1. Download and install the U12's installation package.

LabJack U12 Low Cost USB DAQ connected via USB

Connect U12

2. Connect the U12 to the computer via USB.The U12's status LED should immediately blink 4 times (at about 4 Hz), and then stay off while the computer enumerates (installs) the U12. Earlier versions of Windows will bring up a hardware install window, and you should accept all defaults if prompted. After enumeration the LED will blink twice and remain solid on.

LJLogger: U12 Compatible USB DAQ Application

Run LJLogger

3. LJLogger is a free application installed by the U12 's installation package. You should be able to find it in the Start Menu links.

LabJack Applications

Explore other LabJack Applications

Look at the other applications compatible with the U12 on the U12 Applications page.

LabJack Example Code

Look at the available example code

LabJack develops and maintains example code compatible with the U12. Look at the U12 Example Code and Wrappers page for more details.

Go to the U12's Quickstart page for more detailed instructions.

Datasheet and Application Notes

Product Support Resources - App Notes

LabJack API Documentation

LJM Modbus Map

LJM Modbus Map - Use this tool to discover device features and while developing software to double check register types, names, and functionality.

Application Notes

Application Notes

Application Notes - In-depth detail on various DAQ topics.