E14-140M Low-cost external ADC/DAC module with USB 2.0 interface

Low-cost external ADC/DAC module with USB 2.0 interface
  • ADC: 14 bit / 200kHz
  • Synchronization of ADC, including several modules
  • Input channels: 16 differential or 32 with "common ground"
  • Digital input/output: 16/16
  • 2 channels of 16-bit DAC (optionaly)
  • Built-in ARM processor (32 bits, 48 MHz, 64 KB RAM, 256 KB Flash)

Inexpensive module for the creation of portable measuring systems based on a laptop. Interface USB 2.0 (full-speed). Does not require an additional power source.

Software selects the measurement ranges, sampling frequency and configuration of ADC inputs as differential / with "common ground". Synchronization of the ADC is possible by external clock or by the level of the input signal. There is a mode of inter-module synchronization.

32-bit ARM processor installed on the module and running at the sampling rate of 48 MHz, is available for user programming (in C language).

There is an option to install a two-channel 16-bit DAC. In addition, there are digital inputs and outputs.

Number of channels 16 differential or 32 with "common ground"
Resolution 14 bits
Effective resolution 13,3 bits (100 kHz, measuring range 2.5 V)
Input impedance (at single-channel mode) Not less than 10 MOhm
Input signal measuring ranges ±10 V; ±2,5 V; ±0,6 V; ±0,15 V
Maximum conversion frequency 200 kHz (for internal or external hardware synchronization)
  • Internal
  • By external synchro-signal
  • By analog signal level

Multi-module synchronization is possible.

Inputs protection ± 30 V (power on)
± 10 V (power off and at suspend mode)
Type AT91SAM7S256
Sampling rate 48 МГц
Internal data RAM 64 Кбайт
Internal program EPROM 256 Кбайт
DAC (option)
Number of channels 2
Resolution 16 bits
DAC setting time 0,7 μs
DAC operation mode Synchronous, asynchronous
DAC maximum conversion frequency 200 kHz
DAC conversion frequency grid 200 kHz / n, where n=1,2,...,8
Output range ±5 V
Output current, no more than ±10 mA
Digital inputs and outputs
Number of outputs 16 parallel, asynchronous with common resolution outputs
Number of inputs 16 parallel, asynchronous
Synchronization inputs and outputs Input of controller interrupt,
ADC synchronization input/output
Type of logic CMOS (74 HCT) - TTL-compatible
Power supply  from the USB bus
Consumption current Up to 240 mA (in active mode without DAC),
up to 380 mA (in active mode with DAC)
Outputs for supplying external circuits +5 V, up to 100 mA,
± 15 V, up to 20 mA for each of the circuits (option)
Dimensions — 129x95x26 mm

Signal connectors

The description of signals is given in Manual. Also use the connection examples.

  • E14-140-M
    E14-140-M module, DAC is absent
  • E14-140-MD
    E14-140 module with dual-channel DAC


  • e14_140_programmers_guide.pdf (filesize: 1 461 110 bytes, date: 28.10.2009)

    E14-140 (USB 1.1) module. Programmer's Guide. Lusbapi Library 3.3. Adobe Acrobat 6.0.

  • e14_140_users_guide.pdf (filesize: 2 066 185 bytes, date: 04.12.2020)

    E14-140 and E14-140-M (USB 1.1) modules. User’s Guide.

Software for Windows

  • lusbapi34.exe (filesize: 2 450 812 bytes, date: 09.02.2012)

    Lusbapi Library v.3.4 for Windows 98/Me/2000/XP/Vista/7. Self-extracting archive with the software for the following L-CARD USB devices:

    • E14-140 module (Rev. "A" and "B")
    • E14-440 module
    • E20-10 module (Rev. "A" and "B")
    • E-154 module

    The archive includes USB driver, library, and examples.

    Attention!!! This version of the library uses a new USB driver. Thus, when upgrading from older versions of Lusbapi to version 3.2 or higher, the end user should switch the USB module to work with the new driver via the "Device Manager".

  • lcomp.exe (filesize: 6 342 216 bytes, date: 12.05.2021)

    Beta version. LCOMP library for Windows XP/Vista/Win7/Win8/Win10 32 and 64-bit versions with drivers. The installer and drivers are digitally signed. The library is built on the basis of modern WDM-drivers rewritten on WDF. It includes the WDM driver itself for L-CARD hardware, the DLL library with source code, programming examples, electronic description, etc. The LCOMP library provides support for almost the entire range of products: PCI boards, USB modules. ISA support is excluded.

    The library includes “L-Graph I” software. L-Graph I supports the following devices: L-1450, L-761, L-780, L-783, L-791, E14-140, E-154 and E14-440. Files recorded by L-Graph I can also be read and processed using the demo-version of PowerGraph v.3.X.

LGraph2 software package

  • lgraph2.zip (filesize: 26 786 707 bytes, date: 11.10.2021)

    LGraph2 is a free multi-channel data recorder for Windows. Version 2.35.20 provides the possibility of simultaneous data visualization and recording from the ADCs: L-502, L-780M, L-783, L-791, E-502, E14-140, E14-140M, E14-440, E-154, E20-10, LTR11, LTR114, LTR27, LTR212, LTR216, LTR22, LTR24, LTR25, LTR51. It requires an updated version of the LComp driver (from version 01.04.2010) and ltrserver (no lower than


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