The Analog/Digital IO (ADIO) Board is an off- the-shelf, complete data acquisition system in a compact PC/104 packaging. The analog section contains 32 input channels, multiplexed A/D converter with 16 bit resolution and 10uS conversion time. Input ranges are +/-5v or +/- 10V. It also includes on-board DMA support. The analog output section includes two 12 bit D/A converters. Both sections features simplified calibration using on board programmable digital potentiometer. The digital I/O section provides 24 digital I/O lines, which feature high current TTL drivers. The board requires only +5V from the system power supply and generates its own +/-15V analog supplies on board. The board operates over the Extended Temperatures range of -25 to +85C. Figure 1-8depicts the ADIO board and Figure 1-9depicts the ADIO block dia- gram.
Figure 1-8. ADIO Board
The ADIO board features automatic calibration of both analog inputs and outputs for enhanced accuracy and reliability. The potentiometers, which are subject to tampering and vibration, have been elimi- nated. Instead, all A/D calibration adjustments are performed using an octal 8-bit DAC. The DAC values are stored in an EEPROM and are recalled automatically on power up. The board includes three precision voltage references for negative full scale, zero, and positive full- scale. A calibration utility program provided with the board allows you to recalibrate the board anytime, in both unipolar and bipolar modes, and store the new settings in EEPROM.
Autocalibration applies to the 4 D/A channels as well. The full-scale D/A range is selected with a jumper block. The analog outputs are fed back to the A/D converter so they can be calibrated without user in- tervention. Again, calibration settings are stored in EEPROM and automatically recalled on power-up.
b.Analog Inputs
The ADIO board provides split configura- tion capability, with more total input chan- nels than any other PC/104 analog I/O board. The board can be user-configured in any of three ways:
Channels | Format |
32 | 32 single-ended |
248 differential, 16 single-ended
1616 differential
