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Instruction Manual
748467-A
January 2002
1-10 Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management
Model MicroCEM
1-6 ANALOG/DIGITAL I/O BOARD
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, multi-
plexed 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 in-
cludes two 12 bit D/A converters. Both sec-
tions 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 1-8 depicts the ADIO board
and Figure 1-9 depicts the ADIO block dia-
gram.
Figure 1-8. ADIO Board
a. Automatic Calibration
The ADIO board features automatic cali-
bration of both analog inputs and outputs
for enhanced accuracy and reliability. The
potentiometers, which are subject to tam-
pering 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 automati-
cally on power up. The board includes
three precision voltage references for
negative full scale, zero, and positive full-
scale. A calibration utility program pro-
vided with the board allows you to recali-
brate the board anytime, in both unipolar
and bipolar modes, and store the new
settings in EEPROM.
Autocalibration applies to the 4 D/A chan-
nels 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 re-
called 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
24 8 differential, 16 single-ended
16 16 differential