• U12 Datasheet
• U12 Software & Driver
• U12 Quickstart Tutorial

The LabJack T7 is the most versatile, best bang-for-your-buck DAQ offered by LabJack or anyone else that we know of. Of course, it isn't perfect for every application or project. Compare all LabJack hardware side by side or read a detailed comparison of the different LabJack devices.

LabJack has everything you need to set up your DAQ system. We provide cables, connectors, mounting hardware and other peripherals for installing, connecting or protecting your DAQ device.  

Our optional accessories include: 

• The CB15 is a simple screw terminal breakout for the DB15 connector. 
• The CB37 is a simple screw terminal breakout board for the DB37 connector. It only works with the U6 and T7 devices and can also be paired with the Mux80 for high channel application up to 84 AINs. 
• The Mux80 is an Analog Input Expansion board for the T7 and U6. It is connected directly to the DB37 connector and can allow a single device to read up to 84 AINs. 
• The RB12 Relay Board provides a convenient interface for the LabJack to industry standard relays to interface a LabJack with high voltages/currents. The RB12 relay board connects to the DB15 connector on the LabJack output or input.  
• The LJTick-Divider (LJTD) signal-conditioning module is designed to divide two single-ended higher voltage analog signals down to 0-2.5 volt signals. 
• The LJTick-DAC (LJTDAC) provides a pair of 14-bit analog outputs with a range of ±10 volts. It plugs into any digital I/O block. Up to 10 of these can be used per device to add 20 analog outputs. 
• The LJTick-InAmp (LJTIA) signal-conditioning module provides two instrumentation amplifiers ideal for low-level signals such as bridge circuits (e.g., strain gauges) and thermocouples. Each amplifier converts a differential input to single-ended. 
• The LJTick-RelayDriver (LJTRD) allows 2 digital I/O lines to each control a relay or other moderate load up to 50V/200mA. 
• The LJTick-CurrentShunt (LJTCS) signal-conditioning module is designed to convert a 4-20 mA current loop input signal into a 0.47-2.36 volt signal. 
• The LJTick-Proto (LJTP) consists of an 8x8 grid of holes for prototyping custom signal-conditioning modules.

What is resolution?

Resolution in this context refers to the conversion of an analog voltage to a digital value in a computer (and vice versa). A computer is a digital machine and thus stores a number as a series of ones and zeroes. If you are storing a digital 2-bit number you can store 4 different values: 00, 01, 10, or 11. Now, say you have a device which converts an analog voltage between 0 and 10 volts into a 2-bit digital value for storage in a computer. This device will give digital values as follows:

So in this example, the 2-bit digital value can represent 4 different numbers, and the voltage input range of 0 to 10 volts is divided into 4 pieces giving a voltage resolution of 2.5 volts per bit. A 3-bit digital value can represent 8 (2³) different numbers. A 12-bit digital value can represent 4096 (2¹²) different numbers. A 16-bit digital value can represent 65536 (2¹⁶) different numbers. It might occur to you at this point that a digital input could be thought of as a 1-bit analog to digital converter. Low voltages give a 0 and high voltages give a 1.

In the case of the LabJack U12, a single-ended analog input has a voltage range of -10 volts to +10 volts (20 volt total span) and returns a 12-bit value. This gives a voltage resolution of 20/4096 or 0.00488 volts per bit (4.88 mV/bit).

LabJack devices support asynchronous serial communications using CMOS-level compatible logic. Standards such as RS232 and RS485 support many of the same timings as LabJack asynchronous serial features, but use incompatible logic levels. Additional conditioning circuitry is required to interface RS232/RS485 I/O with LabJack devices. See our T-series documentation below for additional information:

13.7 Asynchronous Serial [T-Series Datasheet]

Note: The DB15, DB25 and DB37 ports on LabJack hardware should not be confused with serial ports; these DB connectors are only used to expand the I/O of LabJack devices.

LabJack quickstart tutorials show new users how to measure a voltage, change a digital I/O, and set the voltage of an analog output using our free software. These tutorials teaches basic software and device functionality, and is also useful as a quick debugging check to verify that I/O on the device are working properly.

• T4 Quickstart Tutorial
• T7 Quickstart Tutorial
• T8 Quickstart Tutorial
• U3 Quickstart Tutorial
• U6 Quickstart Tutorial
• U12 Quickstart Tutorial
• UE9 Quickstart Tutorial (EOL)

Single-ended and differential refer to the reference for a voltage. Single-ended is referred to ground while differential is referred to some other voltage. For a single-ended measurement, the LabJack converts the difference between the voltage at an input and ground. For a differential measurement, the LabJack converts the difference between the voltage at one input and the voltage at another input that is not necessarily ground.

Differential does not refer to whether a signal is positive & negative or positive-only.  The terms for that are bipolar and unipolar.

On the LabJack U3, U12, U6, and T7, analog inputs can set as single-ended or differential via software. Analog inputs on the LabJack UE9 are single-ended only, so an instrumentation amp is needed to convert a differential signal to single-ended, or a pseudo-differential measurement can be made by taking the difference of two single-ended measurements.

Also see the Differential Readings App Note.

Thermocouples are the most common temperature sensor LabJack customers use. All LabJack devices are capable of taking thermocouple measurements but due to a few complications, special care should be taken when reading temperatures from thermocouples.

LabJack Support Engineers have 20+ years of experience guiding our customers through the complexities of thermocouple measurements and have prepared the following materials:

• Thermocouple App Note
• Temperature Sensor App Note
• Thermocouple Troubleshooting Tips
• T4 Thermocouple Tutorial
• T7 Thermocouple Tutorial
• T8 Thermocouple Tutorial
• U3 Thermocouple Tutorial
• U6 Thermocouple Tutorial

The LabJack T8 is the best device for measuring thermocouples due to its 8 isolated analog inputs. For higher channel count application or more budget sensitive projects the T7-Pro or T7 are excellent alternatives.

The first column in the data file written by LJLogUD or LJLogM is a timestamp of seconds since midnight January 1st (Universal Time), 1904.  This is a very common timestamp format that tells us absolute and relative time. 

A complete tutorial of how to convert this to an easy to read format is available here: 

LJLogUD & LJLogM Timestamps

DIO = Digital Input/Output
IO/D/FIO/EIO/CIO/MIO = Somewhat arbitrary monikers for specific DIO ports on different LabJacks. 

Digital I/O stands for Digital Input and Output. Digital Inputs allow a microcontroller to detect logic states, and Digital Outputs allow a microcontroller to output logic states.

Each digital I/O on a LabJack can be individually configured to one of 3 states: input, output-high, or output-low.

Digital Input: A digital input detects if a voltage is above/below a specific threshold. If the voltage is higher than some value, the computer will detect the digital input as high/set/1. If the voltage is lower than some value, the computer will detect the digital input as low/clear/0.

Digital Output: A digital output allows you to control a voltage with a computer. If the computer instructs the output to be high, the output will produce a voltage (generally about 5 or 3.3 volts). If the computer instructs the output to be low, it is connected to ground and produces no voltage.

Example:

Turn an LED On/Off using a digital I/O.

1. Wire the LED as shown. Optionally connect a current-limiting resistor.
2. Set the state of FIO0 to output-high on the computer. The LED will turn on.
3. The LED will turn Off if the state of FIO0 is set to output-low.

If you are using a raw bridge sensor/load cell/strain gauge that is ratiometric (mV/V) and are simply looking for guidance on which products to use, we suggest using a LabJack T7 and LJTick-VRef41 for the best measurements and ease of use.

For a detailed guide read the LabJack Bridge Circuit App Note

The Wheatstone bridge can be used to measure capacitance, inductance, impedance and other quantities.

Keywords: loadcell, strain gauge, strain gage, bridge circuits, potentiometer, raw bridge circuit, H-bridge, iepe, Integrated Electronics Piezo-Electric

All LabJack Datasheets, App Notes, Quickstart Tutorials, Software, Firmware, Drivers, Examples and everything else are available under the Support Tab

Getting Started with LabJack U3

	Install Software 1. Download and install the U3's installation package.
	Connect U3 2. Connect the U3 to the computer via USB.The U3's status LED should blink at power up and then stay solid on. If Windows asks about installing new hardware accept the defaults.
	Run LJControlPanel 3. LJControlPanel is a free application installed by the U3's installation package. You should be able to find it in the Start Menu links.
	U3's Quickstart 4. See the U3's Quickstart page for more detailed instructions.

U6 vs U6-Pro

The U6-Pro has the following additional features:

• Low-Speed and High-Resolution (24-bit) sigma-delta ADC giving access to resolution indices 9 through 12.

OEM Versions

The U6 and U6-Pro come in standard and OEM versions. The OEM versions are intended to be embedded in another device. They are missing the enclosure and most connectors, as it is easier to install connectors than it is to remove them. LabJack can customize the boards to add or remove hardware before shipping for an additional fee. More information on OEM versions can be found in the OEM versions section of the U6 datasheet.

Analog Inputs:

The LabJack U6 has 14 external analog inputs (AIN0-AIN13). AIN0-AIN3 are available on screw terminals and also on the DB37 connector. All 14 analog inputs are available on the DB37 connector.

The maximum input range is ±10 volts, with software selectable gains of x1, x10, and x100. Each analog input can be measured single-ended, or differentially in even/odd pairs. Analog input resolution is 16 bits at max speed (~20 μs conversion time), increasing to 18+ bits at slower speeds (see Section 3.1 - Command/Response and Section 3.2 - Stream Mode). Input impedance is at least 1 GΩ, with typical input bias currents of only 20 nA.

Command/response (software timed) analog input reads typically take 1-4 ms depending on number of channels and communication configuration. Hardware timed input streaming (supported with hi-speed converter only) has a maximum rate that varies with resolution from 4 ksamples/s at 18 bits to 50 ksamples/s at 16 bits.

For more information see the U6 Datasheet. The U6-Pro has all the features of the normal U6 with the addition of an auxiliary low-speed high-resolution (24-bit) sigma-delta ADC. Analog input resolution varies from 19.5 bits (RMS or Effective) at max speed (4 ms conversion time), to 22 bits at slower speeds (160 ms conversion time).

For more information about the analog inputs see Section 2.6 - AIN and Appendix A. For data rate information see Section 3.1 - Command/Response and Section 3.2 - Stream Mode.

Temperature Sensor:

The LabJack U6 has a temperature sensor located very close to the AIN0-AIN3 screw-terminals. Accuracy is ±2 degrees C (max). This sensor is particularly useful for thermocouple cold junction compensation (CJC).

Fixed Current Outputs:

The LabJack U6 has 2 fixed current outputs of 10 μA and 200 μA. These are useful for measuring resistance (resistors, thermistors, RTDs).

Analog Outputs:

The LabJack U6 has 2 analog outputs (DAC0 and DAC1) that are available both on screw terminals and the DB37 connector. Each analog output can be set to a voltage between about 0 and 5 volts with 12-bits of resolution. The analog outputs are based on a true voltage reference.

The analog outputs are updated in command/response mode, with a typical update time of 1-4 ms depending on communication configuration.

For more information see the U6 Datasheet. For more information about the analog outputs see Section 2.7 - DAC and Appendix A. For data rate information see Section 3.1 - Command/Response.

Digital I/O:

The LabJack U6 has 20 digital I/O channels which can be individually configured as input, output-high, or output-low.

The first 4 FIO are available on screw terminals and the DB37 connector. All 8 FIO and 3 MIO are available on the DB37 connector, and 8 EIO and 4 CIO are available on the DB15 connector. Note that on the U6, CIO0-CIO2 are the same as MIO0-MIO2.

Command/response (software timed) reads/writes typically take 1-4 ms depending on communication configuration. The digital inputs can also be read in a hardware timed input stream where up to 16 inputs count as a single stream channel.

For more information see the U6 Datasheet. For more information about the digital I/O see Section 2.8 - Digital I/O and Appendix A. For data rate information see Section 3.1 - Command/Response and Section 3.2 - Stream Mode.

Timers:

Up to 4 digital I/O can be configured as timers. The timers are very flexible, providing options such as PWM output, pulse timing, pulse counting, and quadrature input.

For more information about the timers see Section 2.9 - Timers/Counters and Appendix A of the U6 Datasheet.

Counters:

Up to 2 digital I/O can be configured as 32-bit counters. Since counting is one possible mode of the timers above, the U6 has up to 6 counting inputs.

For more information about the counters see Section 2.9 - Timers/Counters and Appendix A of the U6 Datasheet.

I/O Protection:

All I/O lines on the U6 are protected against minor overvoltages. The AIN lines can withstand continuous overvoltage of ±20 volts, the FIO lines can withstand up to ±10 volts, while the EIO/CIO/MIO lines can withstand up to ±6 volts.

High Channel Count Applications:

By using USB hubs, many LabJacks can be interfaced to a single PC, providing an inexpensive solution for high channel count applications.

The U6 has 3 different I/O areas:

• Communication Edge: Has a USB type B connector. 
• Screw Terminal Edge: Convenient connections for 4 analog inputs, both analog outputs, 4 flexible digital I/O (FIO), and both current sources. The screw terminals are arranged in blocks of 4, with each block consisting of Vs, GND, and two I/O. Also on this edge are two LEDs. One simply indicates power, while the other serves as a status indicator.
• DB Edge: Has 2 D-sub type connectors: a DB37 and DB15. The DB37 has some digital I/O and all the analog I/O. The DB15 has 12 additional digital I/O (3 are duplicates of DB37 I/O).

USB:  All power and communication is handled by the USB interface.

LEDs:  The Power and Status LEDs convey different information about the device.

GND/SGND:  All GND terminals are the same.  SGND has a self-resetting thermal fuse in series with GND.

VS:  All VS terminals are the same.  These are outputs that can be used to source about 5 volts.

10UA/200UA:  Fixed current sources providing 10µA/200µA at a max voltage of about 3 volts.

AIN#:  AIN0-AIN13 are the 14 analog inputs.

DAC#:  DAC0 & DAC1 are the 2 analog outputs.  Each DAC can be set to a voltage between about 0.02 and 5 volts with 12-bits of resolution.

FIO#/EIO#/CIO#/MIO#:  These are the 20 digital I/O, and are also referred to as DIO0-DIO19.  Besides basic digital I/O operations, some of these terminals can also be configured as Timers & Counters (frequency input, PWM output, etc.), SPI serial, I2C serial, and Asynchronous serial.

For information about reading inputs, start in Section 3.  For information about setting outputs, start with the Waveform Generation Application Note.

High Voltage Analog Inputs

• 4 dedicated high voltage analog inputs (±10V, 12-bit resolution)
• Configurable resolution settings

Flexible I/O:

• 8 configurable low voltage analog inputs (0-2.5V, 12-bit resolution) that can function as digital I/O lines

Digital I/O:

• 8 dedicated digital I/O lines (EIO4-EIO7 and CIO0-CIO3)

Analog Outputs:

• 2 Analog Outputs (10-bit, 0-5 volts)
• Additional analog outputs are possible via the LJTick-DAC

The U6-Pro has the following additional features:

• Low-Speed and High-Resolution (24-bit) sigma-delta ADC giving access to resolution indices 9 through 12.

Our engineers in Colorado, USA, provide real-time live chat. Click the chat bar at the bottom right of any page, or see our Contact page for other ways to get in touch with us.

AIN (Analog Inputs)

A1. My analog input is stuck on some wrong value.

• See Suspicious Values.

A2. My analog input is returning varying values but not the right value.

• See the Troubleshooting Your Analog Input Signal App Note.

A3. My readings are too noisy.

• See Too Much Noise.

A4. How do I measure temperature using a thermocouple, RTD, thermistor or other?

• Start on the Temperature Sensors App Note.

A5. My thermocouple readings are wrong.

• Determine if the error is from the cold junction sensor, the A/D conversion, or the signal itself.
• If the cold junction reading is off by a few degrees that error will show up in your calculated thermocouple temperature.
• Remove the thermocouple, and instead jumper the analog input (or both analog inputs for differential) to GND. The thermocouple voltage is now 0.0 volts which is saying both ends of the thermocouple are at the same temperature and thus the thermocouple temperature you calculate will be equal to the cold junction temperature.
• Remove the thermocouple from the system under test and instead just set it next to the LabJack so the thermocouple is measuring air temperature near the LabJack. If the terminals you are connecting to are at air temperature (e.g. CB37 terminals), the expected voltage is 0.0 volts. If the terminals you are connecting to are warmer than air temperature (e.g. T7 terminals), the expected voltage is a negative value dependent on the temperature difference.
• See Thermocouple Complications.
• See Thermocouple Troubleshooting Tips.

A6. I need to monitor a 4-20 mA current loop signal or measure some other current.

• LabJack analog inputs measure voltage. The LJTick-CurrentShunt is an easy way to convert 4-20 mA to voltage.  See the Measuring Current App Note.

A7. Should I use differential?

• Sometimes it is required or a good idea. See Why use Differential.

A8. Problem with differential analog inputs.

• The signals cannot be totally floating.  See Differential inputs must have a reference.
• See Differential Test.

A9. How do I read from a load cell?

• Most load cells are raw bridge circuits.  See the Bridge Circuits App Note.

A10. How do I measure pressure?

• See the Pressure Sensors App Note.

A11. Can I measure AC or DC?

• Yes, both. When you ask for 1 sample from the LabJack you get the voltage at that moment.  If the signal is DC, you expect multiple samples over time to return the same value.  If the signal is AC, the samples are taken at different points of the waveform and thus will return different values.
• If you want to acquire the waveform for an AC signal, you simply acquire multiple samples over time, which is often done using stream mode.  Then if wanted you can do math on the waveform to determine parameters such as max/min, RMS, or frequency.
• On T-series devices you can use the AIN-EF system to acquire multiple samples over time, do some math, and return various values that describe the multiple samples (RMS, Peak-to-Peak, Period, Average, Max/Min).
• See the Measuring 120/240 VAC App Note.

A12. What is the max data rate?

• We have lots of detail for sample rates.  U12, U3, U6, UE9, T-Series.
• For stream mode we usually specify the max sample rate. For max scan rate divide the max sample rate by number of channels. SampleRate = ScanRate * NumChannels.
• Extended channels on the Mux80 act just like normal channels.  The max sample rate of the LabJack is still the same, you just use a bigger number for NumChannels in the above equation.

Graphical applications for device configuration or basic data collection: LabJack applications. Programming for custom behavior: the C/C++ LJM library or any LJM language wrapper.

For the full list, see this list of T7 Software Options.

Analog Input

• 14 Analog Inputs built in (16-24 Bits Depending on Speed & Device Type)
• Expand to 84 analog inputs with Mux80 add-on
• T7: 16-bit high-speed ADC (up to 100k samples/s)
• T7-Pro: 24-bit low-speed ADC (resolution as low as 1uV noise-free)
• Software Configurable Resolution Settings
• Single-Ended Inputs (14) or Differential Inputs (7)
• Analog input ranges: ±10V, ±1V, ±0.1V and ±0.01V
• All analog input features are software programmable by configuring the Analog Input Registers
• High speed sampling configurable by using Stream Mode. Speeds up to 100kS/s
• Low Latency Sampling and Control (less than 1ms) is made easy with Command-Response Modbus messages
• Easy integration with sensors like thermocouples, load cells, bridges, and more ...

Analog Output

• 2 analog outputs (12-bit, 0-5V)
• Waveform generation via Stream Out
• Integrated LJTick-DAC support for multiple +/-10V outputs

Digital I/O

• 23 Digital I/O
• Supports SPI, I2C, and more... (Master Only)
• 5 PWM Outputs with individual phase control
• 5 Pulse Outputs with configurable number, frequency, and width
• 2 Frequency Inputs returning both frequency and period
• 2 Pulse Width Inputs measuring time spent high and low as well as duty cycle
• 2 Line-to-Line Inputs measuring the time between edges on 2 different lines
• 4 High-Speed Counters
• 6 Software Counters with debounce capabilities
• 3 Pairs of Quadrature Inputs
• Many of these DIO Extended Features share pins and cannot be used at the same time. See the DIO Extended Features section of the T7's datasheet

Fixed Current Outputs

• 200 µA
• 10 µA

Communication Options

• USB
• Ethernet
• 802.11b/g WiFi (T7-Pro only)

Other Highlights

• Capable of stand-alone operation by running Lua Scripts
• Built-In CJC Temperature Sensor for easy thermocouple temperature readings
• Watchdog system
• Field Upgradable Firmware
• Programmable Startup Defaults
• Industrial temperature range (-40 to +85C)
• For more information please visit the hardware overview section of the T7's datasheet

Further Reading

More technical specifications about the T7 can be found in Appendix A of the T7's Datasheet.

What is the difference between the T7-Pro vs. T7?

• 802.11b/g WiFi connectivity. (antenna included)
• Low-Speed and High-Resolution (24-bit) sigma-delta ADC.
• Battery Backed RTC for stand-alone data logging.
• Factory Installed 4Gb+ microSD card for stand-alone data logging.

LabJack Devices:

• Can comfortably operate within the industrial temperature range (-40°C to 85C)
• Are capable of being mounted via DIN Rail/LJ-Snap2d
• Integrate with Voltage Dividers for 24+ Volt signals
• NEMA 3 (or greater) enclosures recommended for any outdoor or indoor applications with dust, debris or in condensing humidity environments
• All LabJack products are covered by our industry leading 5 year warranty
• Have OEM Versions available for custom and embedded applications. 
• Drawings and CAD Models Provided 
• LabJack products are very robust, but subject to the influence of user connections.
• LabJack is not liable for any losses, expenses or damages beyond the LabJack device itself.  See our Limitation of Liability for more details.

UD= U3, U6, UE9

Flexible I/O:

The first 16 I/O lines (FIO and EIO ports) on the LabJack U3-LV can be individually configured as digital input, digital output, or analog input. In addition, up to 2 of these lines can be configured as timers, and up to 2 of these lines can be configured as counters. On the U3-HV, the first 4 flexible I/O are replaced with dedicated high-voltage analog inputs.

The first 8 flexible I/O lines (FIO0-FIO7) appear on built-in screw terminals. The other 8 flexible I/O lines (EIO0-EIO7) are available on the DB15 connector.

For more information, see Section 2.5 - Flexible I/O (FIO/EIO) of the U3 Datasheet.

Analog Inputs:

The LabJack U3 has up to 16 analog inputs available on the flexible I/O lines. Single-ended measurements can be taken of any line compared to ground, or differential measurements can be taken of any line to any other line.

Analog input resolution is 12-bits. The range of single-ended low-voltage analog inputs on the U3-LV is typically 0-2.4 volts or 0-3.6 volts, and the range of differential analog inputs is typically ±2.4 volts (pseudobipolar only). For valid measurements, the voltage on every analog input pin, with respect to ground, must be within -0.3 to +3.6 volts.

On the U3-HV, the first 4 flexible I/O are replaced with dedicated high-voltage analog inputs. The input range of these channels is ±10 volts or -10/+20 volts. The remaining 12 flexible I/O are still available as described above, so the U3-HV has 4 high-voltage analog inputs and up to 12 low-voltage analog inputs.

Command/response (software timed) analog input reads typically take 0.6-4.0 ms depending on number of channels and communication configuration. Hardware timed input streaming has a maximum rate that varies with resolution from 2.5 ksamples/s at 12-bits to 50 ksamples/s at about 10-bits.

For more information see the U3 Datasheet. For analog input information see Section 2.6 - AIN and Appendix A. For data rate information see Sections 3.1 - Command/Response and Sections 3.2 - Stream Mode.

Analog Outputs:

The LabJack U3 has 2 analog outputs (DAC0 and DAC1) that are available on the screw terminals. Each analog output can be set to a voltage between 0 and 5 volts with 10-bits of resolution.

The analog outputs are updated in command/response mode, with a typical update time of 0.6-4.0 ms depending on communication configuration. The analog outputs have filters with a 3 dB cutoff around 16 Hz, limiting the frequency of output waveforms to less than that.

For more information see the U3 Datasheet. For analog output information see Section 2.7 - DAC and Appendix A. For data rate information see Section 3.1 - Command/Response.

Digital I/O:

The LabJack U3 has up to 20 digital I/O channels. 16 are available from the flexible I/O lines, and 4 dedicated digital I/O (CIO0-CIO3) are available on the DB15 connector. Each digital line can be individually configured as input, output-high, or output-low. The digital I/O use 3.3 volt logic and are 5 volt tolerant.

Command/response (software timed) reads/writes typically take 0.6-4.0 ms depending on communication configuration. The first 16 digital inputs can also be read in a hardware timed input stream where all 16 inputs count as a single stream channel.

For more information see the U3 Datasheet. For digital I/O information see Section 2.8 - Digital I/O and Appendix A. For data rate information see Section 3.1 - Command/Response and Sections 3.2 - Stream Mode.

Timers:

Up to 2 flexible I/O lines can be configured as timers. The timers are very flexible, providing options such as PWM output, pulse/period timing, pulse counting, and quadrature input.

For more information see the U3 Datasheet. For timers information see Section 2.9 - Timers/Counters and Appendix A.

Counters:

Up to 2 flexible I/O lines can be configured as 32-bit counters.

For more information see the U3 Datasheet. For counters information see Section 2.9 - Timers/Counters and Appendix A.

I/O Protection:

All I/O lines on the U3 are protected against minor overvoltages. The FIO lines can withstand continuous voltages of up to ±10 volts, while the EIO/CIO lines withstand continuous voltages of up to ±6 volts.

High Channel Count Applications:

By using USB hubs, many LabJacks can be interfaced to a single PC, providing an inexpensive solution for high channel count applications.

The U3-HV has the following differences versus the U3-LV:

• First 4 flexible I/O are changed to dedicated HV analog inputs.
• 4 HV inputs have ±10 volt or -10/+20 volt range.
• 12 LV inputs (flexible I/O) still available, for 16 total analog inputs.

OEM Versions

The U3-LV-OEM or U3-HV-OEM includes the board only without the enclosure and without most through-hole components. See Section 2.12 of the U3 Datasheet for more information.

LV (Low-Voltage) Version:

• 16 Flexible I/O (Digital Input, Digital Output, or Analog Input)
• Up to 2 Timers (Pulse Timing, PWM Output, Quadrature Input, ...)
• Up to 2 Counters (32-Bits Each)
• 4 Additional Digital I/O
• Up to 16 12-bit Analog Inputs (0-2.4 V or 0-3.6 V, SE or Diff.)
• 2 Analog Outputs (10-Bit, 0-5 volts)
• Supports SPI, I2C, and Asynchronous Serial Protocols (Master Only)
• Supports Software or Hardware Timed Acquisition
• Maximum Input Stream Rate of 2.5-50 kHz (Depending on Resolution)
• Capable of Command/Response Times Less Than 1 Millisecond
• Built-In Screw Terminals for Some Signals
• OEM Version Available
• USB 2.0/1.1 Full Speed Interface
• Powered by USB Cable
• Drivers Available for Windows, Linux, Mac and Pocket PC
• Examples Available for C/C++, VB, LabVIEW, Java, and More
• Includes USB Cable and Screwdriver
• Free Firmware Upgrades
• Money Back Guarantee
• Enclosure Size Approximately 3" x 4.5" x 1.2" (75mm x 115mm x 30mm)
• Rated for Industrial Temperature Range (-40 to +85 Degrees C)

HV (High-Voltage) Version:

Same features as the LV version except:

• First 4 Flexible I/O are Changed to Dedicated HV Analog Inputs.
• 4 HV Inputs have ±10 Volt or -10/+20 Volt Range.
• 12 LV Inputs (Flexible I/O) Still Available, for 16 Total Analog Inputs.

For more technical specifications look at the U3's datasheet.

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.

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 Appendix B Page.

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.

Counter:

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.

LabJack enclosure and OEM drawings and models are provided in several neutral file formats. Please see the links below to navigate to the correct LabJack.

• LabJack T4
• LabJack T7
• LabJack U3
• LabJack U6
• LabJack U12

• 20 Digital I/O-Use our CB15 Terminal Board for access to all DIO
• Supports SPI, I2C, and more... (Master Only)
• up to 9 PWM Outputs with individual phase control
• up to 9 Pulse Outputs with configurable number, frequency, and width
• up to 9 Frequency Inputs returning both frequency and period
• up to 9 Pulse Width Inputs measuring time spent high and low as well as duty cycle
• up to 3 pairs Line-to-Line Inputs measuring the time between edges on 2 different lines
• up to 8 High-Speed Counters
• up to 16 Software Counters with debounce capabilities
• up to 8 Pairs of Quadrature Inputs

Many of these DIO Extended Features share pins and cannot be used at the same time. See the DIO Extended Features section of the T8's datasheet

LabJack hardware can be connected to nearly any analog or digital sensor. Of course some sensors are easier than others to connect. If you haven't yet purchased your sensors please check out our App Notes for detailed guides and best practices. Generally the best sensors output an analog voltage in the 0-10v DC range. We have many signal conditioning modules we refer to as "Ticks" that make it easy to accept other signals and ranges

• LJTick-Current Shunt for 4-20mA signals
• LJTick-Divider for voltages over 10v
• LJTick-Vref for sensors that require a stable excitation/power source
• LJTick-Resistance for RTDs, Thermistors or resistive sensors
• LJTikc-InAmp for amplifying tiny signals like bridge circuits or thermocouples

Recommended Software

Though LabJack devices can be used with a variety of software options, we recommend the following—unless you already know what software you'd like to use.

If you'd like a graphical application for device configuration or basic data collection, see the available LabJack applications.

If you'd like to write a program for custom behavior, LabJack recommends the following:

T-Series (T4, T7, T7-Pro, T8)

Windows, Linux, and macOS: LJM library (C/C++) or any LJM language wrapper.

For the full list, see the T-series software options.

• 8 Fully Isolated, differential Analog Inputs built in
• 1kV channel-to-channel and channel-to-ground isolation
• 24-bit high-speed ADC (up to 40,000 samples per second per channel) (Appendix A-1)
• Simultaneous, independent ADC per channel
• Software Configurable Resolution Settings
• Voltage Ranges: ±11V, ±9.7V, ±4.8V, ±2.4V,±1.2V, ±0.6V, ±0.3V, ±0.15V,±0.075V, ±0.036V, and ±0.018V (Appendix A-3-3)
• All analog input features are software programmable by configuring the Analog Input Registers
• High speed sampling configurable by using Stream Mode. Speeds up to 40kS/s/Ch
• Low Latency Sampling and Control (less than 1ms) is made easy with Command-Response Modbus messages
• Easy integration with sensors like thermocouples, load cells, bridges, and more Explore LabJack's Sensor App-Notes

LJM Library

using LabJack;

    ...

    int handle;
    LJM.OpenS("T7", "USB", "ANY", ref handle);

    // Read the voltage on AIN0
    double voltage;
    LJM.eReadName(handle, "AIN0", ref voltage);

    ...

Available AIN Extended Features

For any given AIN channel, one AIN-EF feature may be selected. AIN-EF indices:

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.

Basics: Individual digital I/O lines can be set to digital input or digital output. DIO is a generic name used for all digital I/O.

Common Uses: For wiring information on open-collector signals, driven signals, controlling relays, and mechanical switches, see the Digital I/O (App Note).

How to read and write DIO: See 3.0 Communication for communication basics. Also, LabJack Kipling's Dashboard tab shows live DIO values.

DIO Extended Features: T-series DIO Extended Features expose more complicated features such as:

• Timers, Counters, PWM, Quadrature Input, and more.

Digital Communication Protocols: T-series DIO lines can also be used to communicate with a large number of sensors that require the use of various digital communication protocols. The T-series devices implement the following protocols:

• I2C - Also reference the I2C Lua Library and Lua I2C Sensor examples.
• SPI
• SBUS
• 1-Wire
• Asynchronous Serial (UART)

• 2 analog outputs (16-bit, 0-10V)
• Waveform generation via Stream Out
• Source Impedance/Load Current compensated up to 20mA
• Vout Min -0.0 Vout Max 10.0

The DACs on the T8 use additional power systems to output voltage levels above and below the supply. This allows the T8 to output approximately -0.1 to 10 V as long as the supply voltage is within the valid operating range.

The DACs on the T8 have good load regulation. Very little voltage drop is expected up to 20mA, usually 1-2 mV.

See Appendix A-4 for more information.

Please see your device Quickstart Tutorial.

High Voltage Analog Inputs

Flexible I/O:

Digital I/O:

Analog Outputs:

Timers:

Counters:

OEM Versions

The T4-OEM includes the board only without the enclosure and without most through-hole components. See the OEM Versions section of the T4 datasheet for more details.

AI or AIN = Analog Input
ADC = Analog to Digital Converter

An analog input converts a voltage level into a digital value that can be stored and processed in a computer. Why would you want to measure voltages? There are a multitude of sensors available which convert things like temperature, pressure, etc. into voltages.  The voltages can then be easily measured by various kinds of hardware, such as a LabJack U3-HV, and then read into a computer.  The computer can then convert the voltage value into it's original type (temperature, pressure, etc) and the value can then be stored in a file, emailed to someone, or used to control something else outside of the computer.

Example:

Get temperature from a sensor using an analog input.

1. Wire the output of the analog temperature sensor to a U3-HV as shown.
2. Read the voltage on the computer to know the current temperature. 
3. This particular sensor outputs 0.01 volts per °F, so 0.76V corresponds with 76°F.

Explore LabJack's Analog Input App Note