PC/104 Analog I/O Board


  • Eight true differential inputs, or eight single-ended inputs optional
  • Programmable input ranges of:
      0-5V, 0-10V, 5V, 10V
  • 100KHz sampling rate
  • On-board pacer clock and counter timers
  • Four double-buffered analog outputs
  • Jumper selectable output ranges of:
      0-5V, 0-10V, 5V, 10V
  • 24 digital I/O lines, type 82C55 with change of state detect on port C, buffers on ports A & B
  • Flexible configurations to suit your needs

Factory Options: (call for pricing and availability)

  • 4-20mA inputs with offset
  • Channel by channel pre-amplifier gains of 1-100
  • +5VDC only operation
  • 0 to +70°C and -40 to +85°C versions available
  • RoHS Available. Please contact us for ordering information


The following functions are available in many configurations giving the user the ability to specify exactly whats needed. Interrupts are individually or globally enabled or disabled via software. A status register is provided to determine the interrupt source.


The Analog Inputs feature software programmable gain with ranges of 0-5V, 0-10V, 5V, and 10V. The configuration employs an instrumentation pre-amplifier per channel which allows for differential inputs, 200V Common Mode Rejection, high input impedance, and optional factory channel by channel pre-settable gain (1-200) to accommodate low-level inputs from sensors. Inputs 4-20mA are available as a factory-installable option.


Output ranges of 0-5V, 0-10V, 5V and 10V, are field selectable with jumpers. Note that four conversions may take place at once and that, since the D/As are double buffered, data for the next conversion may be loaded simultaneously.


The circuit uses an 82C54 (3 sixteen bit counter/timers). The user has access to each counter/timers gate, clock, and output signals. The output of counter two can be used to generate an interrupt. The software package supports counting events, frequency output, pulse and frequency measurement.


The circuit uses an 82C55A PPI with mode 0 supported. Ports A and B (16 lines) are buffered and pulled up to 5V. Port C features Change of State detection.


The package includes a graphical Windows setup program detailing all jumper settings. Also included are drivers, samples and utilities for DOS, Windows operating systems (XP -> 10, both 32 & 64 bit), and Linux. Full register-level support for use in custom real-time or embedded operating systems.

Drivers and Downloads

List of available Downloads: Software Packages, Drivers, Manuals, and other documents

Custom Software

ACCES also offers Custom Software Services for our products. Our prices are unbelievably low, often as inexpensive as free! If you need something tweaked to support your needs, or an entire enterprise application developed from scratch, it is definitely worth your time to inquire with us, first.

Available Reference Manuals

Available Software Downloads

Available Datasheets

Further information about available ACCES Software:

Redistributing Windows Drivers
A list of ACCES drivers and the files that compose them under different versions of Windows, so you can easily redistribute ACCES cards and drivers.


Analog Inputs

  • No. of Channels: Eight true differential inputs, or eight single-ended inputs optional
  • Programmable Ranges: 0-5V, 0-10V, 5V, 10V, (4-20mA as a factory option)
  • Conversion Frequency: 100K Samples per Second
  • Resolution: 12-Bit
  • Differential Input Impedance: 2Meg Ohms w/pre-amp
  • Preamplifier gain: 1 standard, Optional gains up to 200 upon request
  • Reference Output Voltage: 4.096V 0.02V
  • Common Mode Voltage: 200V
  • Common Mode Rejection Ratio: 86dB typical
  • Integral Nonlinearity: 1 LSB maximum, Monotonic
  • Full Power-Down Mode: 1µA maximum
  • Standby Power-Down Mode: 400µA maximum
  • Accuracy: 0.2% of full scale
  • Gain Temperature Coefficient: 6 ppm / C typical, bipolar; 8ppm/ C typical, unipolar
  • Noise levels: 1 LSB typical
  • A/D triggering method: Software selectable: programmable timer, program command

Analog Outputs

  • Channels: 4
  • Voltage Ranges: 0-5V, 0-10V, 5V, 10V
  • Conversion Frequency: 100K Conversions per second
  • Resolution 12-Bit
  • Output Drive Capability: 3 mA per channel
  • Power-Down Mode Current Draw: 1µA, maximum
  • Relative Accuracy: 2 LSB, typical
  • Trigger Source(s): Software selectable: programmable timer, program command

Digital Inputs/Outputs

  • Programmable Peripheral Int.: 82C55A
  • Channels: 24, pulled up to 5V via 10K (or pulled down to ground factory option)
  • Buffered Channels: 16 (ports A & B)
  • Input Voltage: Logic low: -0.03V min, 0.8V max;
  • Logic High: 2.2V min, 5.8V max
  • Input Current: ±1uA Max
  • Output Voltage:
    • Logic low: 0.0V min, 0.4V max
    • Logic High: 3.7V min, 5.0V max
  • Output Current:
    • Ports A and B
      • Logic low: 64mA Sink
      • Logic High: 32mA Source
    • Port C
      • Logic low: 2.5mA Sink
      • Logic High: 2.5mA Source
  • Modes supported: Mode 0 (1 and 2 are factory options)
  • Change of State Detection 8 inputs (port C)


  • Peripheral Interface Timer: Type 82C54
  • Counters 3 x 16-Bit down counters
  • Clock Frequency Output: 1Mhz
  • Inputs/Outputs Fully Buffered
  • Native Modes: Pulse on terminal count, retriggerable one-shot, rate generator, square wave, software triggered strobe, hardware triggered strobe.
  • Software Support: Event Counter, Frequency Output, Frequency and Pulse Measurement


  • Power Required (using ±12V and +5V):
    • +12VDC: 30 mA typical
    • -12VDC: 30 mA typical
    • +5VDC: 40 mA typical
  • Power Required (using only +5V, with the optional DC/DC Converter):
    • +5VDC: 240 mA
  • Environmental: 0C to +70C standard, optional -40C to +85C
  • Interrupt Requests: Eleven channels, IRQ 3-7, 9-12, 14, 15
  • Interrupt Status Register: Indicates source(s) of interrupt
  • Interrupt Enable/Disable: Software Controlled

CE testing & approval must be done at the system level, in the designed enclosure, and is not done on individual boards.

ModelPrice (USD)

Acquisition, Control, Communication: Engineering and Systems

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